The last decade has seen psychology research increasingly acknowledge the limitations of only researching WEIRD populations – that is, Western, Educated, Industrialized, Rich & Democratic (Henrich et al., Reference Henrich, Heine and Norenzayan2010). By doing so, it is recognized that some human experiences are not universal, and findings from overrepresented subsamples cannot be generalized as being representative of the entire human population. Psycholinguistic research has been complicit in this too, with a small number of languages from a small number of countries being vastly overrepresented in the field. It is estimated that only around 0.6% of the world’s languages have featured in sentence production research (Jaeger & Norcliffe, Reference Jaeger and Norcliffe2009), with areas such as child language acquisition not being much higher at around 1.5% (Kidd & Garcia, Reference Kidd and Garcia2022). Such is the weighting toward specific varieties from specific countries, that Anand et al. (Reference Anand, Chung and Wagers2011) report that only ten languages account for 85% of the abstracts featured in 4000 leading psycholinguistic conferences and journal articles. Relatedly, Kidd and Garcia (Reference Kidd and Garcia2022) demonstrate that 85% of this language acquisition research comes from authors based in North American and European institutions, with the United Kingdom being the second most prolific country after the United States. Given the geographical and cultural barriers that can exist in accessing diverse global populations (see: Anand et al., Reference Anand, Chung and Wagers2011), it is perhaps not surprising why so much psycholinguistic research is conducted with undergraduate students, in university settings, within highly industrialized societies. Yet, even within these supposedly easier to access populations, researchers often fail to capture the experiences of those who use Minority, Indigenous, Non-standard(ized), and Dialect (MIND) varieties alongside a standard language, because such varieties are not always afforded the same recognition as languages with higher status. As the phrase “a language is a dialect with an army and a navy” would suggest, the distinction between language and dialect is often socio-political rather than based on any technical linguistic criteria. How varieties are organized into systems that reflect social identity is something of considerable interest and debate amongst sociolinguists (see: Eckert, Reference Eckert2012; Guy & Hinskens, Reference Guy and Hinskens2016), who posit that speakers have cognitive awareness of these features (Guy, Reference Guy2013). Yet the lack of an explicit connection with sociolinguistics can be detrimental to the recognition and inclusion in psycholinguistic research of those who speak their MIND.

One exemplar of a MIND variety in a WEIRD environment is “Scots,” spoken in Scotland. Alongside Cornish, Irish, Manx Gaelic, Scottish Gaelic, Ulster-Scots, and Welsh, Scots is recognized by the European Charter for Regional or Minority Languages as a minority language that is indigenous to the United Kingdom. Both Modern Scots and English are West Germanic varieties that descend from a common ancestor. However, while Scots once held the status of a full national language used across all domains of public and private life (Unger, Reference Unger2010), over the few past centuries it has undergone a process of dialectalization (see: Millar, Reference Millar2006) and has seen a considerable drop in status. Losing many of its distinctive lexical and grammatical features has led to the view that Scots is an “incomplete language” (Costa, Reference Costa2015), which is exacerbated by the fact there is no commonly accepted standardized written form of Scots (Unger, Reference Unger2010). Thus, in the present day, Scots is sometimes not only thought of as a non-standard regional dialect of English, but is often considered “bad English” (Shoba, Reference Shoba2010). While 1.5 million people report using Scots (Scottish Census, 2011), many speakers themselves do not see this variety as being separate from English, with one Scottish Government (2010) survey showing that 65% of respondents consider Scots not as a language but “just a way of speaking.” Yet, in this diglossic situation, speakers of English and Scots regularly switch between these varieties depending on the social environment and their fellow interlocutors. Such action might require the use of cognitive language control mechanisms that have been demonstrated for bilinguals (for an overview of these processes see: Declerck, Reference Declerck2020; Declerck & Philipp, Reference Declerck and Philipp2015) despite these speakers generally identifying as English monolinguals.

Investigations into this phenomenon for so-called “bidialectals” have found that active speakers of Dundonian (an urban variety of Scots spoken in Dundee) and (Scottish Standard) English – and even those with only passive knowledge of the local dialect – display symmetrical switch costs that are reminiscent of bilinguals switching between two equally dominant languages (Declerck et al., Reference Declerck, Özbakar and Kirk2021; Kirk et al., Reference Kirk, Kempe, Scott-Brown, Philipp and Declerck2018). On the other hand, (Anglo-) English speakers who had newly learned Dundonian displayed asymmetrical switch costs with a greater cost associated with switching to their more dominant variety (Kirk et al., Reference Kirk, Kempe, Scott-Brown, Philipp and Declerck2018). This asymmetry is presumably due to the greater amount of inhibition required to suppress the stronger representations of English, compared to the weaker, newly learned Scots items (see: Green, Reference Green1998). More recently, it was found that speakers of Orcadian Scots, a rural variety spoken in the Orkney Islands situated off the north coast of Scotland, also displayed asymmetrical switch costs as well as other bilingual language control markers that suggest Orcadian Scots is their more dominant variety (Kirk et al., Reference Kirk, Declerck, Kemp and Kempe2022). This is surprising given that English was not newly acquired by these speakers, unlike the dialect learners in Kirk et al. (Reference Kirk, Kempe, Scott-Brown, Philipp and Declerck2018), and would be their main literary language.

Crucially, without a sensitive measure to capture the use and knowledge of an additional regional variety, all of the aforementioned speakers would likely be regarded as (English) monolinguals, because Scots is generally not given the status of a language. This could potentially render studies comparing such “monolinguals” with more traditionally recognized bilinguals as questionable at best if their cognitive profiles are fundamentally similar but are not properly accounted for (e.g., the bilingual executive control advantage, see: Kempe et al., Reference Kempe, Kirk and Brooks2015; Kirk et al., Reference Kirk, Fiala, Scott-Brown and Kempe2014).

Encouragingly, psycholinguistic research investigating the cognitive effects of bilingualism has become more sensitive to factors such as age of acquisition (e.g., Byers & Yavas, Reference Byers and Yavas2017), active vs inactive bilingualism (e.g., de Bruin, Bak, & Della Salla, Reference de Bruin, Bak and Della Sala2015), bimodal bilingualism (i.e., using spoken and signed languages; Emmorey et al., Reference Emmorey, Mott, Meade, Holcomb and Midgley2021), degree of proficiency (e.g., Singh & Kar, Reference Singh and Kar2018), and usage contexts (e.g., Beatty-Martínez et al., Reference Beatty-Martínez, Navarro-Torres, Dussias, Bajo, Guzzardo Tamargo and Kroll2020). Yet factors such as the sociolinguistic status and prestige of varieties, the relative distance between language pairs, and even what constitutes a language, minority language, or dialect are not always addressed. With many studies failing to provide any sociolinguistic information about their participants’ language usage (Surrain & Luk, Reference Surrain and Luk2019), it is also unclear as to whether labels such as “bilingual” and “monolingual” are applied consistently across the field.

Several psycholinguistic studies categorize speakers of varieties that are closely related (both linguistically and geographically) as “bidialectal,” such as speakers of Standard and Swiss German (Vorwerg et al., Reference Vorwerg, Suntharam and Morand2019) and Nyorsk and Bokmal (Lundquist & Vangsnes, Reference Lundquist and Vangsnes2018). Yet in other studies, speakers of language pairs that might have similar sociolinguistic relationships to those mentioned previously are already given the status of “bilingual” such as Dutch-Frisian bilinguals (Blom et al., Reference Blom, Boerma, Bosma, Cornips and Everaert2017) and Italian-Venetian dialect bilinguals (Lorenzoni et al., Reference Lorenzoni, Santesteban, Peressotti, Baus and Navarrete2021).

Compounding the issue of who should be considered bilingual is the general perception of what constitutes a unique language. Wagner et al. (Reference Wagner, Bialystok and Grundy2022) recently investigated this by asking participants to rate vignettes of fictionalized language systems. Varieties that were unrelated to other languages, that had a written form, and were spoken widely were considered more language-like than those that were related to other varieties, did not have a writing system, and were spoken in more geographically specific areas. Furthermore, individuals were considered more bilingual when both their language varieties had a written form that they had competence with. With these findings in mind, it is perhaps no surprise that the Scots speakers outlined earlier would not be typically recognized or self-identify as bilingual.

As there is no objective standard for distinguishing between dialects and languages, and no fixed boundary line for the level of knowledge, proficiency, or usage that determines the point at which a monolingual becomes a bilingual, self-categorization of language experience is incredibly subjective. Castro et al. (Reference Castro, Wodniecka and Timmer2022) demonstrate that out of 970 self-identified English monolinguals from the UK, 80% had learned some form of language, dialect, or type of jargon, with 40% reporting having been passively exposed to foreign languages or dialects in their environment. This demonstrates the lack of homogeneity that is sometimes assumed about monolinguals and again emphasizes the need for sensitive measures to capture the MIND experiences that exist in WEIRD environments and beyond. As acknowledged by Castro et al. (Reference Castro, Wodniecka and Timmer2022), standard measures such as the Language and Social Background Questionnaire (LSBQ; Anderson et al., Reference Anderson, Mak, Keyvani Chahi and Bialystok2018) and the Language Experience and Proficiency Questionnaire (LEAP-Q; Marian et al., Reference Marian, Blumenfeld and Kaushanskaya2007) might unwittingly fail to capture these experiences. For example, the LSBQ asks participants to “List all the languages and dialects you can speak and understand…”, which might not account for passive knowledge and exposure, or infrequent use of certain varieties. Likewise, the original LEAP-Q refers simply to “languages” throughout, which could prevent respondents from providing information about varieties that are not ideologically considered languages.

There are, however, reasons to be optimistic as more inclusive approaches to capturing diverse language experiences increasingly become available. Since its inception, the original LEAP-Q has been adapted for 22 different languages and a range of dialect and socio-cultural contexts (Kaushanskaya et al., Reference Kaushanskaya, Blumenfeld and Marian2020). Perhaps the further framing of questions away from “language” toward descriptions such as “way(s) of speaking” (to illicit information about the comprehension and production of spoken languages for example) could encourage participants to self-report these underrepresented varieties. Such wording appeared to resonate with those surveyed about their perception and use of Scots as “just a way of speaking” (Scottish Government, 2010). This terminology might also capture the use of within-language registers (such as formal vs informal or adult vs infant-directed speech). While this could provide more granularity than might be required by many bilingualism studies – and may entirely eradicate the concept of being truly “monolingual” – recent research has also demonstrated that switching registers invokes language control mechanisms that are similar, although not identical, to language switching (Declerck et al., Reference Declerck, Ivanova, Grainger and Duñabeitia2020).

Likewise, as there are increasing calls for bilingualism research to produce more detailed assessments and descriptions of bilingual experiences (de Bruine, Reference de Bruin2019), so too are there appeals for more diverse theoretical approaches. Encouraging a paradigm shift in the study of bilingualism, López et al. (Reference López, Luque and Piña-Watson2021) have posited a move toward a more holistic, intersectional, and resilient model of bilingualism research. This is proposed by incorporating raciolinguistics, which seeks to examine the relationship between language and race and how ideas of race influence language and language use (Alim et al., Reference Alim, Rickford and Ball2016). For example, ideas of monolingualism and bilingualism are viewed differently through a raciolinguistic lens. López et al. (Reference López, Luque and Piña-Watson2021) describe the situation where if a white monolingual enters a dual-language classroom they are assumed to be acquiring a skill to enhance education and employment, whereas the language abilities of bilingual Black, Indigenous, and People of Color (BIPOC) are “racialized, viewed as inferior, and assumed to be in need of correction” on entering a similar environment. Relatedly, using a raciolinguistic perspective Cushing and Snell (Reference Cushing and Snell2022) investigated the language ideologies that are “deeply embedded” in England’s school inspectorate institution (known as Ofsted). In doing so, they highlight the intersectionality between race and class as two facets that are discriminated against by a standard language ideology, which also views regional non-standard varieties as “ignorant, sloppy, and impure.”

If speakers are made to feel that their MIND varieties are inferior, then it is no surprise that they are often coded as monolingual by omitting to disclose their use of marginalized varieties, especially those that are not recognized as “languages.” Thus, there is the need for a more ecological approach to fully capture the experiences of bilingual individuals, particularly of speakers of minoritized varieties that are evaluated through a lens in which monolingualism is perceived as the norm. However, in a world where true monolingualism might be rarer than initially assumed (Castro et al., Reference Castro, Wodniecka and Timmer2022), we need to MIND our languages and continue to ensure that MIND varieties and the experiences of those who use and understand them are fully captured in our research.