Grammaticalization and language contact in a discourse-pragmatic change in progress: The spread of innit in London English

Abstract This variationist analysis investigates the development and spread of innit as an invariant tag in London English. The sociolinguistic distribution of innit in a socially stratified corpus of vernacular speech suggests that the form's emergence and spread were initiated and propelled system-internally through changes associated with grammaticalization. Frequency triggered phonetic reduction of isn't it to innit; loss of syntactic-semantic usage constraints and growing functional versatility enabled innit to seize the range of contexts and functions of grammatically-dependent tags (e.g. didn't you, weren't we), virtually ousting these from the system of negative-polarity interrogative tags. Examination of cross-linguistic data and comparisons with relevant pre- and non-contact varieties indicate multiple language contact and grammatical replication may have played an ancillary role. I flag some challenges of establishing contact effects in discourse-pragmatic change, and propose that the promotion of innit for invariant use was governed by its low salience and social indexicality of localness. (Innit, question tags, (Multicultural) London English, grammaticalization, language contact, grammatical replication)*

(1) a. I mean, it's immoral, isn't it. (Monty, old-M-A-multi) b. We've been on two Mediterranean cruises, haven't we. (Shirley, old-F-A-mono) c. Cos they don't know me, do they. (Latif, 16-M-A-multi) (2) a. Potato is good for you, innit. (Tina, b. But next year, she'll get paid, innit. (Mandy, 18-F-A-mono) c. You get dazed, innit. (Alex, Innit derives from isn't it, possibly via ain't it, and is spreading beyond third-person singular neuter present-tense  vs. (2b,c)), suggesting its development into an invariant tag which can be appended to any anchor irrespective of grammatical properties and which may eventually oust the dependent tags in (1) (Krug 1998;Andersen 2001). I use the Linguistic Innovators Corpus (LIC), with an apparent-time span of seventy-odd years (Kerswill, Cheshire, Fox, & Torgersen 2007), to test these predictions and whether the associated changes are (i) an example of grammaticalization, 'the process by which a frequently used sequence of words or morphemes becomes automated as a single processing unit' (Bybee 2003:603), and=or (ii) a product of multilingualism, an environment that 'provides particularly good conditions for the development of invariant ['is þ it' tags]' (Andersen 2001:113). My analysis implicates grammaticalization and, possibly, multiple language contact in changes affecting several aspects of the London English system of negative-polarity interrogative tags (NEG-TAGS): variant inventory, linguistic conditioning, and functional profile. Central to these changes is the rapid spread of innit across social groups and linguistic contexts, at the expense of other NEG-TAG variants.

B A C K G R O U N D
Innit (or ennit), pronounced [ɪnɪt] or [ɪnɪʔ], has been widely used in southern England since at least the 1970s by working-class youth of diverse ethnicity, acquiring local vernacular status in London (Cheshire 1982:61;Sutcliffe 1982Sutcliffe :184, 1992Hewitt 1986:126-32). Without explaining the origins of the form innit, early observers attributed its spread to ethnic minority speech. Hewitt (1986:126-32) and Sutcliffe (1992:90, 104) claim use of innit in extended contexts, as in (2b,c), originated in British Jamaican Creole. Baumann (1996:47) and Harris (2006:100-101) link innit to London adolescents of South Asian descent. Krug (1998) and Andersen (2001) provide corpus-based confirmation of innit's use and spread in southern England. Andersen quantifies its distribution in the Bergen Corpus of London Teenage speech (COLT, 1993) and subsets of the British National Corpus (BNC=London, 1991. Although used across social groups, Andersen finds innit is most frequent among females, adolescents, and individuals from lower social classes and ethnic minority backgrounds, especially when used as in (2b,c) beyond its presumed source context after third-person 724 Language in Society 50:5 (2021) singular neuter present-tense BE-anchors. The findings support Hewitt's (1986) and Sutcliffe's (1992) proposals: SOME uses of innit may spread from ethnic minority speech. Yet Andersen's basis for evoking language contact-multilingualism promoting invariant 'is þ (-n'tþ) it' tags in other contact varieties-is problematic (see Thomason & Kaufman 1988:57-59).
Despite occurrence of innit across anchor types, its linguistic distribution in COLT is more frequent after anchors licensing dependent tag variants that are phonologically complex (e.g. mustn't they), involve certain low-frequency modals (e.g. ought she), or share syntactic-semantic features with the tag isn't it (e.g. isn't he, hasn't it). Based on syntactic-semantic constraints, Andersen (2001:197) argues innit derived through phonetic reduction and fusion from isn't it: [ɪznt ɪt] . [ɪzn ɪt] . [ɪn ɪt]. He does not exclude derivation from ain't it via in't it (see Krug 1998:182), but notes this pathway is not supported by his data, where (a)in't-tags are infrequent and innit rarely occurs in hasn't it contexts (see derivation of ain't from both present-tense BE and HAVE; Cheshire 1981:366).
The sociolinguistic conditioning of innit in Andersen's data reveals change indicative of ongoing grammaticalization. Innit is predominantly used with thirdperson singular neuter present-tense BE-anchors by adults and by adolescents from higher classes and Hertfordshire, whereas (ethnic minority) adolescents from lower classes and London regularly use innit across anchor types. However, in keeping with Hopper's (1991:28-30) Principle of Persistence, whereby distribution of grammaticalizing features is constrained by their origin, innit is favoured after anchors licensing dependent tags with 'it', forms of BE, present-tense auxiliaries, and negative polarity. For Andersen, these patterns show innit's hostclass expansion, led by male and ethnic minority speakers and accompanied by pragmatic strengthening (see also Erman 1998), is gradual and ongoing. Based on distribution of third-person singular neuter present-tense BE-tags in the BNC and Bank of English Corpus (1980-), Krug (1998) predicts innit's gradual spread across all anchor types to replace the canon of dependent tag variants. Torgersen, Gabrielatos, Hoffmann, & Fox (2011) compare innit's normalized frequency (= N=million words) and spread (= % innit users) across subsamples of COLT and LIC. They find neither frequency nor spread of innit differ significantly across the two datasets collected twelve years apart nor across social factors (sex, ethnicity, borough) in LIC. They conclude 'the use of innit seems to have stabilised [and] is no longer characteristic of a particular group of speakers' (Torgersen et al. 2011:107). While grammaticalization is often associated with frequency increase (Bybee, Pagliuca, & Perkins 1994:8;Bybee 2003:602), frequency increase may lag behind context expansion (Mair 2004). Frequencies (and spreads) are therefore not reliable means to assess whether linguistic change involving expansion of an innovating feature across linguistic contexts and social groups is ongoing.
Palacios Martínez (2015) explores the linguistic distribution of innit among COLT and LIC adolescents (without circumscribing the variable context). He claims that, between 1993 and 2005-2006, innit increased in frequency after Language in Society 50:5 (2021) 725 non-BE anchors, and with the functions 'emphatic marker' and 'text organiser'. Since Palacios Martínez does not provide comparative data for innit's distribution across anchor pronouns, explain the 'text organiser' function or consider social predictors, the nature, direction, and extent of the form's context expansion remain nebulous. colleagues (2011) andPalacios Martínez (2015), then, neither refute nor validate Krug's (1998) and Andersen's (2001) hypotheses about the spread of innit. Nor do they clarify the role of grammaticalization and language contact.
Previous studies also neglect that innit may not be the only NEG-TAG variant undergoing change. Cheshire & Fox's (2009) analysis of past-tense BE in LIC shows that adolescents in outer London use the tag form weren't it after anchors which, in Standard English, do not license third-person singular neuter past-tense BE-tags, as in (3). Cheshire & Fox hypothesize that weren't it may be grammaticalizing as an invariant tag in parts of London.

A V A R I A T I O N I S T A P P R O A C H T O I N N I T
My variationist analysis of innit in London English differs from earlier studies in three aspects.
(i) Recognizing that linguistic forms do not evolve in systemic isolation, I include in the locus of variation the CANON of NEG-TAGS (see Labov's 1972:72 'principle of accountability'). This situates the development of innit within the linguistic subsystem where it first emerges and subsequently operates, and establishes how its development is shaped by and shapes activities in the remainder of the NEG-TAG system (see Weinreich, Labov, & Herzog's 1968:185 'embedding problem'). (ii) Because grammaticalization is socially embedded and constituted of multiple directional changes (Bybee et al. 1994:12-14;Nevalainen & Palander-Collin 2011:128), I operationalize broad social factors and MULTIPLE diagnostics of grammaticalization as (in)dependent variables for quantitative analysis, and examine their COMBINED effect on variant selection using mixed-effects modelling. Comparisons of the structure of variant choice across social groups and stages in NEG-TAG change expose the existence, directionality, and social dimension of ongoing grammaticalization (see Narrog & Heine 2011;Poplack 2011;Tagliamonte 2013). (iii) Applying Poplack & Levey's (2010:406) and Thomason's (2013) imperatives, I test contact hypotheses by examining (a) the structure and conditioning of question tags in presumed MODEL LANGUAGES, and (b) the distribution of innit in appropriate PREand NON-CONTACT VARIETIES. Cross-linguistic and cross-dialectal comparisons elucidate factors triggering and propelling observed NEG-TAG changes (see 'actuation' and 'transition' problems in Weinreich et al. 1968:184-86).

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Language in Society 50:5 (2021) The data were extracted from the 1.4-million-word Linguistic Innovators Corpus (LIC, 2005(LIC, -2006Kerswill et al. 2007), collected through sociolinguistic interviews with older adults (ages sixty-two to ninety) and adolescents (ages sixteen to nineteen) from selected multi-and mono-ethnic London boroughs. Table 1 stratifies the 110 NEG-TAG users in LIC by social predictors. (Eleven LIC speakers with below-average word counts produced zero NEG-TAGS.) Beyond borough and sex, the adolescent sample is divided by ethnicity as a broad indicator of language background (see Cheshire, Adger, & Fox 2013:54): a homogenous group of largely monolingual individuals of long-standing white British heritage (Anglos), and a heterogeneous group of individuals of ethnic minority and recent immigrant heritage who tended to regularly use a heritage language (non-Anglos). (All old speakers are Anglo.) Andersen (2001:195) concludes that innit originates in and spreads from ethnic minority speech. Invoking non-Anglo ethnicity as a measure of advanced innit use and employing the apparent-time framework (Bailey 2002), I infer evidence for ongoing NEG-TAG change from the variable's differential patterning across old Anglos, young Anglos, and young non-Anglos. Comparison of NEG-TAG distributions across ethnicity and borough flags the potential role of language contact in NEG-TAG innovations. Inclusion of speaker sex identifies which-males or females-are leading observed changes.

NEG-TAG variable (context)
Situating the evolution of innit in relation to the linguistic subsystem in which it originates requires (i) operationalizing innit as a linguistic variable and isolating the whole set of forms with which it alternates in this subsystem, and (ii) delimiting the analysis to those contexts where speakers have a choice between co-variants (Labov 1972:71-72). Implementing these requirements in discourse variation analyses is not straightforward (see inter alia Pichler 2010;Waters 2016). Like other discourse-pragmatic features, innit is semantically bleached and polyfunctional, hampering identification of co-variants based on semantic equivalence (Labov  (Lavandera 1978;Dines 1980). Moreover, innit is referentially and syntactically optional, which complicates determining where it could have occurred but did not (Labov 1982:30). To provide an accountable analysis, I use derivational and positional criteria for defining the variable (context). I include in the analysis the canon of reduced negative-polarity interrogative tags (NEG-TAGS) derived from the linear string of components '(auxiliary) þ (negative clitic) þ (pronominal subject)' and attached to same-speaker positivepolarity declarative anchors (see also Pichler 2013:179). This definition delimits the analysis to a finite set of variants equivalent in component parts (even if not easily identifiable in cases of advanced reduction=fusion), leftward scope over same-speaker propositions, and persistent or fading grammatical dependency on declarative anchors. It excludes constructions which, in LIC, are invariable or have different scopal properties: NEG-TAGS after negative-polarity, imperative, and interrogative anchors; and tokens in pre-finite or turn-initial positions (e.g. One person, innit, was a bit weak; A: He's got to win. B: In he!; see further Pichler 2016). Positive-polarity and invariant tags (e.g. do you, yeah) are excluded. The former compete only marginally with innit in LIC. The latter constitute a category of question tags by definition unconstrained by anchor grammatical properties (Axelsson 2011:802-806), and therefore not comparable to innit in its initial attestations as dependent NEG-TAG. Without function as inclusion criterion, I can operationalize semantic-pragmatic shift as one of multiple quantitative measures of grammaticalization (Schwenter & Torres Cacoullos 2008:11-12;Pichler 2010:587-91).

Extraction and exclusions
I applied a Perl script designed to exhaustively extract all full, reduced, and fused '(auxiliary) þ (negative clitic) þ (pronominal subject)' combinations from LIC while simultaneously discarding ineligible hits (e.g. don't you immediately preceded by a WH-word). I manually inspected the search results, LIC transcripts, and audio files to remove ineligible extractions (e.g. haven't you immediately followed by a VP), add tokens not isolated by the script (e.g. wunnit), and check the transcription of NEG-TAGS and anchor materials. Following standard variationist procedure, I removed NEG-TAGS with uncertain variant form or indecipherable anchors, and those part of direct quotes and meta-linguistic commentaries. This left 2,359 NEG-TAG tokens for analysis.

Coding
To assess whether London English NEG-TAG changes can be understood with reference to grammaticalization, I operationalize as (in)dependent variables the processes jointly constituting grammaticalization and together signalling constituency change (Heine 2003 Erosion and fusion. All NEG-TAG tokens were subjected to auditory analysis to confirm their morphophonological properties and identify the full inventory of NEG-TAG variants in LIC. For quantification, I categorize individual variants by degree of erosion and overt manifestation of unithood status. The 'full' category contains phonetically non-reduced variants analyzable as three distinct morphemes (auxiliary þ negator þ pronoun). The 'reduced' category contains variants derived through phonetic reduction and, occasionally, fusion from full variants. Reduction processes affect auxiliary vowels (e.g. aren't . ain't) and, if present, final consonants of auxiliary stems (e.g. wouldn't . wun't). (With both full and reduced variants, the =t= of negators is sometimes deleted.) With exception of innit and consistent with other reduced variants, in-, din-, dun-, win-, and wun-forms in LIC (e.g. dun we, wunnit) near-categorically combine with pronouns that match the anchor subject (e.g. He always smiles, in he), suggesting they are not fixed but constructed on-line from distinct negative auxiliary-and pronoun-morphemes (see Beckner & Bybee 2009). Innit, by contrast, regularly occurs in contexts where it matches neither the grammatical properties of the anchor verb nor subject (e.g. They look gangster, innit), indicating its negative auxiliary-and pronoun-elements, [ɪn] þ [ɪt], have been reanalysed as a single unit, [ɪnɪt], that is stored and accessed holistically as one chunk (Andersen 2001:201-202;see Bybee 2003see Bybee , 2010 on 'chunking').
Because of its different constituent structure and centrality in the analysis, innit occupies a distinct category. Phonetically reduced=fused forms are located further along the grammaticalization cline than non-reduced and non-fused forms (Bybee et al. 1994:107-108;Hopper & Traugott 2003:158). Occurrence of reduced variants and innit in LIC thus evidences that the London NEG-TAG system has been affected by phonetic erosion and fusion indicative of grammaticalization. The results section establishes the extent of these changes and their impact on the formal composition of the London English NEG-TAG system, including any ousting of variants by the predicted spread of innit (and, possibly, weren't it).
Decategorialization. To assess decategorialization, I followed Andersen (2001) and examined syntactic-semantic ties between NEG-TAGS and anchors. I distinguish four contexts: (i) paradigmatic, in (4), where choice of tag pronoun and auxiliary are constrained by anchor syntactic-semantic properties; (ii) non-paradigmatic, in (5), where the properties of tag pronoun and auxiliary mismatch those of anchor subject and verb; (iii) semi-paradigmatic, in (6), where either the properties of anchor subject or auxiliary are replicated in the tag, but Language in Society 50:5 (2021) 729 not both; and (iv) ambiguous, in (7), where NEG-TAGS' scope and anaphoric reference are unclear. Appendix B details assumptions for coding reduced and fused NEG-TAGS, and NEG-TAGS following elliptical and multi-clausal anchors or anchors with certain semi-auxiliaries. NEG-TAGS with nonstandard pronoun-auxiliary agreement (e.g. weren't he) were coded as if having standard agreement. Used beyond their source context through violation of Standard English form-dependency rules, semi-and non-paradigmatic NEG-TAGS provide evidence of decategorialization. Ambiguous NEG-TAGS also indicate weakening anaphoric links between anchors and NEG-TAGS. Cross-tabulations, reported in the next section, isolate affected variants. I also coded semi-and non-paradigmatic NEG-TAGS for their anchor syntactic-semantic properties in order to establish evidence of persistence in their grammatical distribution (see Andersen 2001:177).
Semantic-pragmatic change. I measure semantic-pragmatic change by conceptualizing NEG-TAGS' multifunctionality as polysemy layering: the coexistence of older and newer discourse functions (Hopper 1991:22-24). I examined the function of each NEG-TAG in LIC using the time-aligned orthographic transcriptions and insights from conversation analysis (Atkinson & Heritage 1984). Utterance interpretation was guided by sequential context, ambient linguistic context (e.g. prosody, hedges), and co-participants' next-turn 730 Language in Society 50:5 (2021) responses. To minimize coder subjectivity, I conducted three independent, blind analyses at six-month intervals, followed by discussion of inconsistent codings with speakers of London English. Using these procedures, I isolated these well-established functions (see inter alia Tottie & Hoffmann 2006;Pichler 2013): seeking verification or confirmation of anchor propositions, mitigating negatively affective speech acts, underlining salient or obvious anchor propositions, and signalling involvement and alignment (see Appendix C for examples). I also uncovered NEG-TAG uses resembling ones described by Andersen (2001:128-32) for innit in COLT, where they function as interactive narrative devices. In (8), Freddy's narrative NEG-TAGS request tacit acknowledgment of the tagged propositions, thereby focusing listeners' attention on and guiding their interpretation of salient story materials (see further Pichler 2021). Unlike other NEG-TAG functions, the narrative function is not attested in diachronic or synchronic British English varieties outside London. Since development of discourse functions is cumulative (Traugott 2016:32), the narrative function in LIC (and COLT) evidences semantic-pragmatic context expansion. I evoke NEG-TAGS' conducive force as another measure of semantic-pragmatic change. Verification-and confirmation-seeking NEG-TAGS invite listener responses, warranting their categorization as conducive NEG-TAGS that meet Hudson's (1975:12) sincerity conditions for interrogatives ('The speaker believes that the hearer knows at least as well as the speaker does whether the proposition is true or false.'). Other NEG-TAG uses do not generally meet these conditions, having comparatively weakened conducive force (see Cheshire 1981;Algeo 1988). I therefore categorize them as non-conducive. (Mitigating NEG-TAGS are exempt; their conduciveness effect varies by context.) Most modern NEG-TAG functions have been attested since the sixteenth century, but seeking verification or confirmation and, by implication, soliciting listener responses are the original uses (Tottie & Hoffmann 2009:154). I therefore construe rise in non-conducive NEG-TAG uses as evidence of pragmatic bleaching or weakening of interrogative force.

Quantification
Distributional analyses examine NEG-TAGS' social patterning along linguistic measures operationalized above to identify and trace NEG-TAG changes in progress. The programming environment R (R Core Team 2016) is used for statistical Language in Society 50:5 (2021) testing. Mixed-effects logistic regressions using the lme4 package (Bates, Mächler, Balker, & Walker 2015) establish the statistical significance of sociolinguistic predictors on variant choice when all of them are treated simultaneously and inter-speaker variation in NEG-TAG frequency and choice is accounted for. In Tables 4-6, significant positive coefficients indicate that specified predictor levels favour application values (compared with specified baseline levels); significant negative coefficients indicate disfavouring effects. 3

R E S U L T S
This section first compares NEG-TAGS' formal, structural, and functional variability across LIC social groups. It then presents mixed-effects logistic regressions that illuminate how ongoing spread of innit (and, possibly, weren't it) restructures the NEG-TAG system, and which social forces and linguistic processes may generate change.
Distributional results Figure 1 partitions the full set of NEG-TAGS into the variant categories assumed to occupy different stages on the grammaticalization cline, showing their frequencies as proportions of all NEG-TAGS produced by each social group. It reveals that phonetic reduction and fusion are implicated in synchronic NEG-TAG variability, and that competition between variant categories is unstable. We observe unidirectional change from a system dominated by full variants (old Anglos) to one where innit is supreme (young non-Anglos), via an intermediate system of more vigorous variation between variant categories (young Anglos) (see 'layering' in Hopper 1991:22-24). Ongoing reconfiguration of the NEG-TAG inventory favours innit, the variant located furthest along the cline of reduction and fusion. Table 2 elucidates the reconfiguration by comparing, across social groups, frequencies of the top ten NEG-TAG variants and total numbers of individual variants used. Because old Anglos use innit, isn't it, and several other full variants with broadly comparable frequencies, innit does not dominate their NEG-TAG system. With innit assuming majority and virtual default status among young Anglos and young non-Anglos, other variants (e.g. don't they) recede, and both size and diversity of the NEG-TAG inventory diminish. Contrasting with Andersen's (2001) COLT data, where innit has lower overall frequency than its assumed source isn't it, innit has effectively replaced isn't it among adolescents in LIC (N = 2 in each group). Rise of innit does not greatly affect the status of ain't it and in't it, alternative precursors to innit; they are consistently negligible or absent (N = 6, N = 7, N = 0 across social groups). Although the second most frequent variant among young Anglos, weren't it is marginal compared to innit.
For each social group, Figure 2 plots on the y-axis proportional frequencies of NEG-TAGS across the syntactic-semantic contexts listed on the x-axis. It furnishes quantitative evidence of ongoing decategorialization: transformation of a grammatically-dependent into invariant NEG-TAG system. Older Anglos' near-categorical use of NEG-TAGS in paradigmatic contexts and robust compliance with Standard English form-dependency rules explains the fragmentation of their variant inventory. Among young Anglos, rise in semi-and non-paradigmatic NEG-TAGS, which bear only partial or no form-dependency on anchors, reduces rates of paradigmatic NEG-TAGS. Weakening of syntactic-semantic ties between NEG-TAGS and anchors is most advanced among young non-Anglos, who predominantly use semi-and nonparadigmatic NEG-TAGS. Small rises in ambiguous tokens also indicate relaxation of anaphoric constraints governing NEG-TAG variability. Table 3 reports NEG-TAG frequencies for each micro-function listed on the left as proportion of all NEG-TAGS produced by the social group listed on top. It shows unstable polysemy layering in the system. First, it provides quantitative confirmation of the semantic-pragmatic innovation described earlier. Use of narrative NEG-TAGS is negligible among old Anglos but slowly rises among young speakers. Second, it reveals reweighting in relative importance of established NEG-TAG functions

Logistic regression results
The model in Table 4 fitted independent regressions of the contribution of sociolinguistic predictors to the choice of each NEG-TAG variant category across all speakers in LIC. For each category, regressions reveal significant main effects of social group, vindicating inference of ongoing change in the formal composition of the London English NEG-TAG system. Old Anglos favour full variants compared to young speakers; the probability of reduced variants significantly increases among young Anglos; young age significantly boosts the odds of innit compared to old age. Coefficients for borough show that-unlike full variants-innit is favoured in multi-ethnic boroughs, suggesting change towards increased use of innit proceeds at different rates across boroughs. (With Bonferroni corrections of p-values to α = 0.0167 to compensate for multiple independent regressions, effect of speaker sex for full variants is marginal.) Results for main effects of linguistic factors identify innit as principal exponent of decategorialization and semantic-pragmatic change. Innit's significant association with semi-and non-paradigmatic and non-conducive compared to paradigmatic and conducive uses establishes its routine use beyond its source context and with pragmatically bleached functions. By contrast, the distribution of full and reduced NEG-TAGS shows little evidence of syntactic-semantic spread or weakening of interrogative force. Both variant categories are favoured in paradigmatic contexts. The main full and reduced forms occasionally used in semi-=non-paradigmatic contexts are weren't it and (a)in(t)-tags (see (5)-(6) above). Yet their main users (young Anglos) follow the same trajectory of change towards increasing use of (invariant) innit as the leaders of change (young non-Anglos) (see Figures 3 and 4). Weren't it is therefore but a transient competitor for invariant status (contra Cheshire & Fox 2009). Regarding function, full variants accommodate to the advancement of non-conducive innit (and polyfunctional reduced variants) by developing a complementary correlation with conduciveness (see Hopper's 1991:24-25 'functional split'). The advancement of innit, then, impacts both probability AND conditioning of full and reduced NEG-TAGS. Table 5 elucidates innit's expansion. It reports results of parallel regressions modelling effects of sociolinguistic predictors on the probability of innit (versus full and reduced variants) at different development stages. Notwithstanding old Anglos' low innit frequency, the results show that innit has not entered the NEG-TAG system as a fully invariant, pragmatically bleached tag. Among old Anglos, there is no main effect of interrogative force. But with increasing frequency, innit first develops then loses correlation with non-conduciveness among Anglo and non-Anglo adolescents. No significant increase in the probability of innit beyond its source context is detected among old Anglos. Only among adolescents does innit Language in Society 50:5 (2021)  737 significantly expand into semi-and non-paradigmatic contexts. Throughout, innit is favoured in ambiguous contexts, suggesting perhaps that scopal under-specification is an inherent characteristic. The data, then, support an interpretation of semanticpragmatic and syntactic-semantic change in progress. Growing functional versatility and weakening syntactic-semantic constraints promote innit in the NEG-TAG system. Figure 3 inspects the syntactic-semantic distribution of innit. Bars along the y-axes show its proportional frequency out of all NEG-TAGS appended to anchors that in Standard English license the tag pronouns and tag auxiliaries on the x-axes. Among old Anglos, innit is virtually restricted to contexts constituting or FIGURE 3. Frequency of innit across tag pronouns and auxiliaries licensed by Standard English tag formation rules. Results for had are not shown due to limited data (N 1 across groups). Other pronoun and auxiliary contexts occur at N 13.

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Language in Society 50:5 (2021) resembling its source: it, (s)he; is, has, was. Among young Anglos, innit spreads across available contexts, its proportional weight exceeding 25% across most pronouns and auxiliaries. Yet as in Andersen's (2001) COLT data, there is evidence of persistence (see Hopper 1991:28-30). Innit is most frequent in contexts fully or partially sharing grammatical properties of its source: it; is, has, does; and it is significantly favoured with it and is over other pronouns and auxiliaries (χ 2 (1) = 148.78, p , 0.0001; χ 2 (1) = 173.65, p , 0.0001). These constraints vanish among young non-Anglos, where innit exceeds rates of 70% across contexts and is not significantly favoured with third-person singular pronouns or is (χ 2 (1) = 3.27, p = 0.07; χ 2 (1) = 1.93, p = 0.16). As predicted by Krug (1998:171), innit has expanded 'to all persons, all verbs (in all tenses) and all subjects' (see also Andersen 2001:203). Old Anglos use innit largely as grammatically-dependent, young non-Anglos as fully decategorialized invariant tag. 4 Returning to Table 5, there is no detected association of innit with male speakers in any social group. Sex effects uncovered by Andersen (2001) in COLT have been neutralized. The main effect of borough among young Anglos and differences in variant conditioning between young Anglos and young non-Anglos in Table 5 warrant closer inspection. Table 6 summarizes results of a regression model fitting main, interaction, and random effects on the probability of innit among the LIC adolescents grouped by ethnicity AND borough. (Data from non-Anglo adolescents in mono-ethnic boroughs were not fitted due to poor sample stratification; see Table 1.) The main effects reveal both Anglo and non-Anglo adolescents in multi-ethnic boroughs significantly favour innit over Anglo adolescents in mono-ethnic boroughs. Results for interaction effects reveal significant interactions between adolescent group and linguistic predictors, visualized in Figure 4. (Ambiguous tokens were modelled but not plotted.) The odds of innit in semi-and non-paradigmatic contexts significantly increase among adolescents in multi-ethnic compared to mono-ethnic boroughs; this increase is sharper for non-Anglos than Anglos. The plot also suggests the interaction effect between adolescent group and interrogative force is driven by young Anglos in mono-ethnic boroughs, who use innit for conducive functions with lower frequencies than adolescents in multi-ethnic boroughs. All adolescents have higher innit frequencies with non-conducive compared to conducive functions, but overall these frequencies are higher among those from multi-ethnic than mono-ethnic boroughs.
In sum, although innit evinces evidence of syntactic-semantic and semanticpragmatic change across ALL young speakers in LIC, the changes are more advanced in multilingual environments (multi-ethnic boroughs) and among multilingual speakers (young non-Anglos). The data provide a basis for pursuing a contact hypothesis for the spread of innit (see Heine & Kuteva 2005), and for adding invariant innit to the catalogue of innovations characterizing Multicultural London English (MLE) (Cheshire, Kerswill, Fox, & Torgersen 2011). My results contradict Torgersen and colleagues' (2011): the use of innit has NOT stabilized, and its proportional frequency and linguistic distribution DO continue to differentiate social groups.

Grammaticalization
The previous section demonstrated that rise of innit within and beyond third-person singular neuter present-tense BE-anchor contexts and across macro-functions is driven by interaction of phonetic reduction and fusion, decategorialization, and semantic-pragmatic shift. These changes are associated collectively with grammaticalization (but see n. 2), and provide multilayered evidence that innit has become 'automated as a single processing unit' (Bybee 2003:603). Evolution of the London NEG-TAG system is in accordance with the unidirectionality hypothesis of grammaticalization: the tendency for formal, structural, and functional changes to proceed in one direction (Hopper & Traugott 2003:99-139). Extrapolated from my results, the multilevel pathway in (9) shows that the changes affecting the system follow universal tendencies of loss and expansion (Bybee et al. 1994;Himmelmann 2004), viz: (i) the reduction of phonetic substance and loss of morpheme boundaries; (ii) the loss of form-dependency constraints with attendant host-class expansion; and (iii) the acquisition of new polysemies and weakening of interrogative meaning components with corresponding semantic-pragmatic context expansion. These developments are neither new nor unique to London English. Diachronic studies of question tags in sixteenth-to twentieth-century drama texts show the system has undergone semantic-pragmatic change from the start (Hoffmann 2006;Tottie & Hoffmann 2009). Apparent-time studies of synchronic speech data reveal phonetic erosion and host-class expansion of NEG-TAGS in contemporary northern British Englishes (Pichler 2013;Childs 2016). What is striking is the interdependence, speed, and magnitude of NEG-TAG developments in London. They affect ALL dimensions of NEG-TAG use-form, structure, and function-, radically transforming the system within the seventy-odd years covered by LIC. But the different changes are intimately connected only for the diachronically and synchronically most frequent auxiliary-pronoun combination in NEG-TAGS: 'is þ it' (see inter alia Krug 1998:152-53;Hoffmann 2006:42-43;Tottie & Hoffmann 2006:296, 2009Pichler 2013:198). The findings thus confirm that grammaticalization need not affect all variants of a variable homogeneously (Bybee & Torres Cacoullos 2009). The findings also suggest the system in which an innovating variant is embedded and the innovating variant itself need not move in the same direction throughout the course of semantic-pragmatic change. The London NEG-TAG system is shifting from conduciveness to non-conduciveness. The macro-functional distribution of innit across social groups in LIC displays seemingly counter-directional changes: weakly conducive . non-conducive . weakly non-conducive. This may be because formal reconfiguration of the NEG-TAG system proceeds faster than its semantic-pragmatic shift. Among LIC young non-Anglos, innit far outnumbers full and reduced NEG-TAG variants, but the NEG-TAG variable as such performs conducive and non-conducive functions with roughly similar frequencies. With almost no full variants in young non-Anglos' repertoire, the functional split between full variants and innit (noted in Table 4) cannot be maintained, and innit must subsume conducive uses (see Hopper's 1991:22 'specialization').

Language contact
London English NEG-TAG development, then, is consistent with a grammaticalization model. But what triggered it? What, if any, is the role of language contact?
Comparisons with relevant pre-and non-contact data from LIC old Anglos and individuals in cotemporaneous northern England corpora undermine the idea of language contact as trigger. LIC old Anglos were born in the 1930s and grew up as monolingual speakers in mono-ethnic neighbourhoods; multilingualism was not part of their early sociolinguistic histories (Cheshire et al. 2013:66-67). Individuals recorded in the northern communities of Hull, Berwick-upon-Tweed, and 742 Language in Society 50:5 (2021) Tyneside share limited experience of everyday multilingualism; at the time of data collection, their communities were virtually mono-ethnic white British (Cheshire, Kerswill, & Williams 2005:144;Pichler 2013:211;Childs 2016:25-27). Assuming adult linguistic stability and rejecting a south-north diffusion hypothesis for innit, 5 LIC old Anglos' and northern individuals' regular use of innit in paradigmatic and, occasionally, semi-and non-paradigmatic contexts is inconsistent with inference of contact-propelled change.
The emergence of the form innit and its spread through the NEG-TAG system must have been triggered by a force not restricted to contact settings: frequency. Owing to high incidence of use in a sequence, the morphemes 'is þ -n't þ it' have undergone phonetic reduction ([ɪznt ɪt] . [ɪzn ɪt] . [ɪn ɪt]) and have been reanalysed as the single processing unit or chunk innit ([ɪnɪt]) (Andersen 2001:196-201;see Beckner & Bybee 2009;Bybee 2010). Unlike its source variant isn't it, innit is not immediately identifiable as a reduced interrogative clause that is composed of the NEG-TAG building blocks 'auxiliary þ negator þ pronoun'. Through loss of analysability and compositionality, innit has gained autonomy from its source. The growing opacity of innit's internal constituency (relative to isn't it) has weakened its syntactic-semantic co-dependency on third-person singular neuter present-tense BE-anchors and induced spread across anchor contexts. In turn, syntactic-semantic context expansion, together with loss of interrogative transparency, have produced new polysemies. Devoid of syntactic-semantic constraints and transparent interrogative structure, innit has spread to past-tense narratives where it developed new non-conducive functions.
An internal causation scenario explains the distribution of innit in the noncontact varieties in northern England. In London English, too, progression of change is compatible with a system-internal evolution of the NEG-TAG system. But this does not explain the timing, social embedding, and unprecedented scale of NEG-TAG changes in London. Changes incipient among LIC old Anglos gained momentum in the late twentieth century in boroughs that experienced increased immigration and linguistic diversification, and among adolescents with probable regular exposure to, or even use of, languages other than English in their families and neighbourhoods (see Cheshire et al. 2013:53-54, 66-67). This calls for consideration of language contact.
Language and dialect contact may have played an ancillary role in the development of the form innit. Hewitt (1986) and Sutcliffe (1992) claim (non-paradigmatic) innit has its origins in British Jamaican Creole. While not listing innit or ennit in their dictionaries of Jamaican and Caribbean English, Cassidy & Le Page (1967:235) and Allsopp (1996:18, 304) note the Creole pronunciation [ɪn] for 'is' and 'ain't'. Although '[ɪn] þ pronoun' is a common tag variant in British Englishes (see inter alia Cheshire 1981:370;Pichler 2013:183;Childs 2016:176), the dictionaries weakly support the idea of Jamaican or Caribbean English influence on the development of the [ɪn]-element in [ɪnɪt] in southern England varieties.
More compelling, though inconclusive, evidence is available to propose that language and dialect contact may have reinforced the syntactic-semantic spread of innit. Table 7 provides an overview of question tags in languages and non-British varieties of English widely spoken in the multi-ethnic boroughs of LIC adolescents (see Baker & Mohieldeen 2000); it includes tags in two ambient creoles and in heritage languages (passively) spoken by frequent (N 10) NEG-TAG users in LIC (Torgersen, pc, February 28, 2017). 6 With the exception of Gujarati and Yoruba, which have exclusively polarity-dependent invariant tags, all languages in Table 7 have neutral invariant tags with no semantic, lexical, or syntactic usage constraints. Only Afrikaans, Hindi-Urdu, and Swahili also have dependent tags with more or less complex grammatical or lexical usage restrictions. All contact dialects have invariant tags, sometimes in addition to lower-frequency dependent tags (not listed). Because invariant tags prevail cross-linguistically (Axelsson 2011) and second-language learners tend to ignore tag characteristics not found in their invariant tag-dominated heritage languages (Kolehmainen, Meriläinen, & Riionheimo 2014:17), ambient learner varieties are likely also characterized by invariant tag usage. Only in ambient varieties of British English are dependent tags expected to be more robust than invariant tags (e.g. yeah, right) (Algeo 1988:175;Stenström, Andersen, & Hasund 2002:185-87). Assuming that the invariant tags listed in Table 7 are known, understood, or used by adolescents in multi-ethnic boroughs, their occurrence may have challenged the status of grammatically-dependent English NEG-TAGS. How?
Language contact may also have boosted semantic-pragmatic developments. Use of English narrative NEG-TAGS (see (8) above), for example, seems limited currently to London. Goria (2016) finds that in bilingual Gibraltar, the Spanish tag no, which does not otherwise serve an emphatic function, underwent semantic-pragmatic context expansion on the English model. Although English invariant tags also regularly occur in narratives (Stenström et al. 2002:165-191;Pichler 2021), pragmatic borrowing, whereby linguistic material 'takes on new discourse functions as a result of external influence' (Andersen 2014:18), may have reinforced the development of innit and other NEG-TAG variants as narrative devices in London. Available sources only attribute agreement-seeking functions to tags found in the frequent heritage languages and dialects in Table 7. But narrative tag functions have been reported for less widely used contact languages: Tamil, Mohawk, and Portuguese (Herring 1991;Mithun 2012;Gómez González 2014).
Contact would shape the course of change. In the system-internal scenario I propose, there is a strong causal and temporal link between processes of change. Phonological changes are primary and cause syntactic-semantic context expansion; phonological and syntactic-semantic change are together responsible for semantic-pragmatic change. In a multiple causation scenario involving contact, however, syntactic-semantic spread of innit is not chiefly enabled by loss of analysability and compositionality. Instead, context expansion is driven by recruitment of innit for grammatical replication. Depending on the scenario, frequency increase of innit is either the source or by-product of context expansion.

Social diffusion
Irrespective of language contact effects, innovations in innit usage are led by speakers of MLE-(non-)Anglo adolescents in multi-ethnic boroughs. How do these innovations diffuse to mono-ethnic boroughs? Regression analyses (not shown) revealed the odds of innit increase significantly among: (i) young Anglos in monoethnic boroughs with the most ethnically mixed friendship networks (compared to those with exclusively Anglo networks), and (ii) adolescents commuting from multi-ethnic to mono-ethnic boroughs for college (compared to those both studying and living in mono-ethnic boroughs). These correlations indicate regular interethnic contact and everyday mundane mobility may constitute important channels for the social diffusion of innit innovations across ethnicities and boroughs (see also Cheshire, Fox, Kerswill, & Torgersen 2008). This would explain why innit is more frequent, less grammatically constrained, and more functionally versatile in mono-ethnic London boroughs than in the mono-ethnic northern locales mentioned 748 Language in Society 50:5 (2021) earlier. The social forces promoting system-internal tendencies in mono-ethnic London boroughs are likely rarer or altogether absent in northern England.

Selection of innit
Following Cheshire and colleagues (2011), I invoke Mufwene's (2001) 'feature pool ' and Siegel's (1997) selection constraints to account for the promotion of innit in the London English NEG-TAG system. Cheshire and colleagues propose that in multi-ethnic boroughs, the high linguistic diversity and largely unguided acquisition of English within ethnically mixed adolescent peer groups produce a feature pool. It contains a complex and heterogeneous set of co-variants drawn from different input varieties spoken in the ambient multilingual environment; in the pool, co-variants compete with and reinforce each other (Mufwene 2001:4-6). Multiple factors such as frequency and unmarkedness conspire to constrain selection from the feature pool (Siegel 1997:139-43). The selection may give rise to new variants or to increased and modified use of original input variants, including ones infrequent in the local variety before language and dialect contact began or intensified (Mufwene 2001:4-6). Table 7 lists input languages and dialects to the 'tag feature pool' in relevant multi-ethnic boroughs. With the exception of Yoruba, all contribute at least one tag form that comprises a negative particle or affix (in bold non-italics); most of these are neutral invariant tags (see final column). Many also contribute forms that comprise a third-person singular neuter pronoun and/or form of BE (in bold italics); these are often (reduced) strings of 'is (þ -n't) þ it' (see final set). Traditional London English contributes dependent tags skewed towards 'is þ it'. We may assume, then, the 'tag feature pool' is heavily biased towards variants that contain 'is þ it', have negative polarity, and=or are invariant. With innit combining multiple or all of these properties in two input varieties, its selection from the feature pool is likely governed by frequency, low salience, unmarkedness, and economy (see Siegel 1997:139;De Smet 2012:608). Innit derives from the feature pool's most common auxiliary-negator-pronoun combination and is commonly used as a dependent tag in one input variety (traditional London English) and as an invariant tag in another (London Jamaican). Moreover, it lacks analysability and compositionality vis-à-vis isn't it and other NEG-TAG variants. Thus, the selection of innit will have been promoted by its gradual spread across social groups and anchor contexts constituting a lowly salient and, by implication, favoured innovation. It extends a pattern already latent in some input varieties; and because of the form's reduced transparency it constitutes a relatively covert rule violation. (Absent detailed descriptions of the functionality of other tags in the feature pool, we can only speculate that innit's selection may have also been affected by its greater multifunctionality; see Hlavac 2006.) Since the gradual expansion of innit is relatively unobtrusive, it is favoured over alternative scenarios, viz: (i) spread of a less frequent and more marked Language in Society 50:5 (2021) 749 auxiliary-negator-pronoun combination (e.g. weren't it); or (ii) wholesale adoption of a fully invariant but lexically marked tag form from a contact language (e.g. Cantonese hóh-mhóu). Due to their pragmatic detachability (Matras 2009), tag forms get routinely borrowed in language contact situations (see, for example, Bentahila & Davies 1983;Goria 2016). In London, tag variants from contact languages may be rejected over innit because they index ethnic minority group membership or nonlocalness (see also Cheshire et al. 2011:167-68). Innit was at first also related to minority status (black Caribbean and, possibly, South Asian heritage). It diffused across adolescent groups, possibly because of its covert prestige as a racialized linguistic form (see Hollington & Nassenstein 2017), and it became delinked from racial or ethnic and relinked to place identity (Hewitt 1986:132; see Aarsaether, Marzo, Nistov & Ceuleers's 2015 'space appropriation'). Because, unlike other variants in the feature pool, it indexes localness, London adolescents may have selected innit for expansion because it helps them foreground their identity as Londoners.
Innit's indexicality of localness, use as an invariant tag in one input variety, and unmarked status in the NEG-TAG feature pool may also have boosted its adoption by bilingual and second-language speakers. Within the NEG-TAG feature pool, innit is unmarked in terms of lexical components ('is þ it'), polarity (negative), and usage restrictions (invariant). In language contact settings, bilingual and second-language speakers tend to adopt unmarked rather than marked features (Thomason 2013:43-44) and replace dependent with invariant tags (Bhaya Nair 1991:213). These speakers may promote selection and expansion of innit in a drive towards economy in the NEG-TAG system, that is, to reduce the complexity and informational redundancy inherent in a grammatically-dependent system. The form's social indexicality would allow them to do so without outing themselves as bilingual or second-language users.
C O N C L U S I O N My variationist analysis of LIC reveals the ongoing transformation of the London NEG-TAG system via successive micro-changes in the sociolinguistic conditioning of co-variants. A system characterized by diversity of full NEG-TAG variants that are grammatically dependent and largely conducive is being supplanted by one that is increasingly non-conducive and dominated by invariant use of one variant: innit. I attribute these developments to formal, structural, and functional changes associated with grammaticalization, triggered by frequency. I propose that-even if not implicated directly-multiple language contact may play an ancillary role in reinforcing the emergence of the form innit, accelerating its expansion across anchor contexts, and shaping functional change in the NEG-TAG system.
My contact proposal remains tentative. We do not know (i) to what extent the tags listed in Table 7 are used in the wider community, (ii) whether adolescents in multi-ethnic boroughs were sufficiently exposed to relevant heritage languages for contact effects to occur, or (iii) whether the published sources in the table

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Language in Society 50:5 (2021) reflect current functional (and structural) usage. To more reliably confirm the role of multiple language contact in discourse-pragmatic change, we need more research into the use of presumed model languages in the multilingual community, metadata about individuals' knowledge and use of these languages, and corpus-based descriptions of relevant model structures.
Among leaders of observed NEG-TAG changes in London (young non-Anglos), innit has spread across syntactic-semantic contexts AND begun to assimilate functions of full and reduced NEG-TAG variants, which earlier dominated the NEG-TAG system and initially occur in complementary distribution with innit. Full and reduced variants maintain a precarious foothold, the former occupying a functional niche (conduciveness), the latter carrying social meaning (young Anglo). Continued spread of innit may endanger the survival of these variants and cause the disappearance of grammatically-dependent NEG-TAGS in young Londoners' vernacular English. With innit having developed into a fully invariant tag in their vernacular, it will be interesting to see how it competes with more established invariant tags such as yeah and right.
N O T E S *I am immensely grateful to Jenny Cheshire and Paul Kerswill for access to LIC (funded by the ESRC). I thank Lauren Ackerman for help with statistics; Khadija Badri for researching parts of Table 7; Sebastian Hoffmann for Perl scripts for data extraction; Eivind Torgersen for answering corpus queries and checking tag transcriptions; and Kaleigh Woolford for R-codes. I am thankful to audience members at DiPVaC4 (Helsinki, 2018), two anonymous reviewers, and Shana Poplack and Elizabeth Traugott for constructive comments on earlier drafts. Ultimate responsibility for the article rests with me.
1 All examples are from the Linguistic Innovators Corpus. Information in parentheses gives speakers' pseudonym, age (cohort), sex (F = female, M = male), ethnicity (A = Anglo, N = non-Anglo), borough (mono = mono-ethnic, multi = multi-ethnic). Transcription conventions are given in Appendix A.
2 Erosion and fusion, decategorialization, and semantic-pragmatic change are, of course, not the only identified processes of grammaticalization (see Lehmann 2015), nor are they unique to grammaticalization (see, for example, Campbell & Janda 2001). Brinton's (2006) work on discourse-pragmatic change has challenged Lehmann's paradigmaticalization and scope reduction criteria, a finding confirmed in my data. Conceived as expansion (rather than reduction; Himmelmann 2004; Traugott 2010), grammaticalization is a useful framework for explaining how discourse-pragmatic features arise and develop over time (see inter alia Brinton 1996Brinton , 2006. (I reject Erman & Kotsinas' (1993) pragmaticalization framework. It overlaps with expansion views of grammaticalization and implies discourse-pragmatic features are a-grammatical.) 3 Notation for significance in Tables 4-6: *p , 0.05, **p , 0.01, ***p , 0.001. 4 An anonymous reviewer proposes expansion of innit involves two abrupt changes: emergence of fixed innit (= addition of grammar B; young Anglos), followed by loss of compositional innit (= loss of grammar A; young non-Anglos) (see Denis 2021). Figure 3 suggests transition between grammars A and B is gradual and 'sneaky', progressing 'from one environment to another on the basis of similarity relations between environments' (De Smet 2012:608). 5 Krug (1998:184) and Cheshire and colleagues (2005:155-59) posit that innit is innovating in and diffusing from southern England varieties. Pichler (2013:211) proposes the occurrence of innit in Berwick English, northern England, is an independent system-internal development; only semi-and non-paradigmatic innit uses diffuse from London. I concur with Pichler (2013) regarding innit's systeminternal origins, but suggest that low rates of semi-and non-paradigmatic innit in northern varieties may Language in Society 50:5 (2021) 751 be due to relative absence of sustained, community-wide language contact as an accelerating force in linguistic context expansion. 6 Corpus studies of question tags in languages other than English are in short supply. The top of Table 7 was collated from reference grammars, review chapters, Moravcsik's (1971) and Axelsson's (2011) tag typologies, and from named individuals, whose help I gratefully acknowledge. It makes no claims to exhaustiveness, serving to assess which tag categories and usage constraints dominate potential models for contact-induced change. third-person singular neuter present-tense BE (Andersen 2001:196-201) College is better, innit.
He must be coming up to 17 now, innit.
They're hyped a bit as well, in't they.
And I was butting my friend, in he.
They love their food, in they.
din(t)-tags present-and past-tense DO I learned from them all, din I.
You got it as well, din't you. dun(t)-tags present-tense DO You get a load of chocolate at Christmas, dun't you.
We're all loud, dun't we.
win-tags modal will He will just get it sorted, win he.
Matthew start again, win he. wun(t)-tags modal will and would The kids would half kill them, wun't they.
You just fail, wun you.  How old is she? Two years older than me, in't she.
What would you want to know about him? -About money, weren't it. multiclausal anchors (e.g. matrixcomplementizer constructions) NEG-TAG scope and anchor materials inferred from context (where possible) Everyone swore that mum got the piano out of the collection money, didn't they.
People think we're mates, innit. Not brother and sister. They just think we're two mates.
We think they're rude, innit.