15.3.1 Scenario 1: Return from an L3 Environment (in Childhood) and L3 Attrition

The first scenario where the return to a bilingual speaker’s homeland may affect an L3 emerges in the case of bilingual speakers who lived in an L3 environment and, at a certain moment of their life, moved (back) to the L1 or the L2 environment. This is the case of bilingual couples who move to or meet in a country where neither of their family languages is spoken. Their children grow up with both their parents’ family languages at home and start to acquire the dominant environmental language as an L3, often in the school context. They lose daily contact with this third language if the family moves back to (one of) the home country(ies).Footnote ¹ For instance, this situation is frequently experienced by families with academic jobs who get a position at an international research center or university.

If studies on returnees from L2 environments are rare, studying returnees moving back from L3 contexts is even more scarce, or almost nonexistent. We report the results from two exploratory case studies that analyze language development in three children after moving back from an L3 context to one of their native language environments. We will then discuss the main research questions related to L3 development that arise from this type of study.

One of the first studies looking at the development of an L3 in returnee children is Reference CohenCohen’s (1989) investigation of the performance of his own two English–Hebrew bilingual children after a one-year stay in Brazil, where the children acquired Portuguese as their L3 and were able to converse fluently in that language. They learned Portuguese mainly through social interactions outside their private Israeli school, for instance through a twenty-one-day excursion with monolingual Brazilians almost six months after living in São Paulo. The children moved (back) to Israel at the ages of almost ten and fourteen and lost contact with Portuguese. Data collection started one month after leaving Brazil and was repeated three and nine months later. Cohen investigated attrition effects in the productive L3 lexicon of the returnees based on a storytelling task (using the well-known Frog, Where Are You? booklet). The results show a decrease in the total amount of lexical items, but also its diversity to retell the story during the nine-month testing period in which the participants lacked contact with Portuguese. Furthermore, greater attrition effects were observed in the younger than in the older sibling, but attrition appeared to be restricted to productive skills since both children recognized most of the words they did not use, even eleven months after the onset of noncontact. The author argues that a prolonged period of lack of contact with the target L3 leads to forgetting processes, even though not to a complete loss of lexicon. In addition, L3 attrition is modulated by age of loss of input, which in turn is linked to degree of literacy.

The second study, by Reference Yildiz and KoyuncuogluYildiz and Koyuncuoglu (2017), investigates attrition effects in the L3 Turkish of an L1 English–L2 French bilingual child from Canada who lived for eleven months in Turkey when she was about six years old. She acquired a high level of fluency in oral Turkish by attending a Turkish-speaking nursery school. After moving back to Canada, she completely lost contact with her L3. Data collection occurred via Skype once a month during eight months through free conversation. Data collection started one month after the child returned to Canada. The study aimed at identifying attrition in Turkish morphology and vocabulary by analyzing code-switching utterances. According to the authors, the “findings have revealed the subtle yet significant changes” in the child’s Turkish (Reference Yildiz and KoyuncuogluYildiz & Koyuncuoglu, 2017: 298), particularly with respect to structurally assigned morphology. For instance, the child started to use analytical structures instead of bound morphemes in the later stages of data collection. The authors acknowledge that a longer period of observation would have been useful to better understand the attrition patterns in Turkish.

One crucial question that arises from these kinds of studies, which investigate the development of an L3 in bilingual returnees who lived for a certain period in the L3 environment, aims at understanding if processes of L3 attrition in bilingual child returnees follow the same trajectories as in L2 attrition. To shed light on this research inquiry we need to compare the findings from L3 studies with the studies on L2 attrition in returnees, even though both types of research are scarce. Thus, much more studies are needed to gain a more coherent picture of this type of bilingual language development.

Most L2 attrition studies involving child returnees are case studies with a reduced number of participants (see Reference Flores, Schmid and KöpkeFlores, 2019 for an overview; an exception are Kubota’s studies on Japanese returnees). Similarly to the two L3 attrition studies, several L2 attrition studies on child returnees present longitudinal analyses of the attrition trajectory in the L2 from the moment of return until some months (and no longer than two or three years) later (Reference KuhbergKuhberg, 1992; Reference Reetz-Kurashige and HansenReetz-Kurashige, 1999; Reference Tomiyama and HansenTomiyama, 1999, Reference Tomiyama2000; Reference Yoshitomi and HansenYoshitomi, 1999; Reference Snape, Matthews, Hirakawa, Hirakawa and HosoiSnape et al., 2014; Reference FloresFlores, 2015). They focus on lexical knowledge, morphosyntax, semantics or, more recently, processing costs and cognitive function (Reference KubotaKubota, 2019; Reference Kubota, Chevalier and SoraceKubota et al., 2020a, Reference Kubota, Chevalier and Sorace2020b, Reference Kubota, Heycock, Sorace and Rothman2020c). Essentially, the degree of L2 attrition observed in these studies varies significantly, which is due to differences in the age of return, the degree of contact with the L2 after moving back, the linguistic domain under analysis, or even the method used. Still, most studies report a decline of proficiency that starts some months after the change of dominant environment, which is more significant in younger returnees.

Overall, the attrition trajectories reported for the L2 seem to be similar to the processes observed in L3 attrition. After some months lacking regular contact with the target language, attrition effects start in the productive lexicon in the form of more frequent instances of code-switching, and move selectively to other linguistic domains. For instance, Isabella, the participant observed by Reference Yildiz and KoyuncuogluYildiz and Koyuncuoglu (2017), started to produce deviant system morphemes in her L3 Turkish within seven months of incubation (i.e., lacking context with the L3). The same is observed in the case of Ana, the participant analyzed by Reference FloresFlores (2015), who started to show attrition effects in her L2 German five months after her return to Portugal. The degree of attrition will depend in both cases, L2 or L3 returnees, on the same factors: the level of proficiency attained in the target language before the moment of return and the amount of exposure to this language after return, in addition to individual factors which may further impact on the attrition process (e.g., motivation to maintain contact with the target language after moving away from its environment). An interesting question, open to investigation, is whether a potential period of stabilization of linguistic knowledge, in the sense of Reference FloresFlores (2010), would apply in the same fashion to an L3. In other words, does an early acquired L3 need the same amount of input and time as an L2 to be acquired and consolidated in the speaker’s mind? Or does the fact that it is an L3 play a role in early language consolidation, precisely because it is in competition with two other languages? From what we already know about multilingual language acquisition in childhood, we would predict that this stabilization period would be similar in L2 and L3 acquisition as long as the language input conditions are similar.

Despite the logical assumption that L2 and L3 stabilization periods should pattern similarly, the fact that bilingual speakers who return from an L3 environment have two childhood languages instead of only one is indeed a crucial variable that distinguishes L2 from L3 returnees. The central question that arises from this particular language scenario is whether the presence of two native languages will accelerate the attrition process due to the competition of two languages in use against the one non-used language. Several studies on 2L1/ L2 returnees have shown strong effects of crosslinguistic influence in various language domains after the returnee moved back to the country of origin. The HL, which now becomes the dominant language, starts to influence the attrited L2 (or 2L1) in several domains. Reference FloresFlores (2012), for instance, revealed such effects of crosslinguistic influence from Portuguese into the returnees’ eroded German in the domain of object expression. After losing regular exposure to German, the group of Portuguese–German returnees that she investigated started to omit object pronouns in German in contexts that do not allow for object omission. This process is interpreted as crosslinguistic influence from Portuguese, which is a null object language. A relevant question that arises from these observations is whether in L3 returnees the processes of crosslinguistic influence would be even more pronounced, since the speaker has two childhood languages competing with the attrited L3. We will explore this question from a theoretical perspective in Section 15.3.3.

15.3.2 Scenario 2: Reacquiring a Lost Language – A Case of Reactivation or L3 Acquisition?

The second scenario involves situations of return or of double return with a focus on the language that starts to be the dominant language after the change of environment. On the one hand, this is the case of the native language that is acquired as the HL while the bilingual individual lives in the migration context. As soon as s/he moves (back) to the country of origin, this HL becomes the dominant environmental language (for a deeper discussion of these cases, see Reference Flores, Schmid and KöpkeFlores, 2019). On the other hand, in the current global mobile society, many families move back to the country of migration after (failed) attempts to return to the homeland. In these cases of double return, the returnee child experiences attrition of the L2 after moving to the L1 context, followed by re-immersion in the L2 context after going back to the context of migration (a situation discussed by Reference FloresFlores, 2020).

What is the relationship of these scenarios with L3 development? The crucial fact in these scenarios is that a language, acquired through naturalistic exposure in childhood, has gone through a period of reduced use or complete deprivation at a certain moment of the bilingual speaker’s life. When the speaker is (re-)immersed in the context where this language is the majority language, exposure is regained and re-acquisition sets in. This raises a central question, namely: is the reacquisition of a previously acquired and lost L1 or L2 an instance of reactivation of a latent language, or is it relearning? In the latter case, we may argue that the language is relearned in the same fashion as it would be as an L3.

This hypothesis has been discussed by Reference PolinskyPolinsky (2015) with a slightly different population, so called “heritage-speakers-turned-learners” (163), heritage speakers who lose daily contact with their HL due to extensive exposure to the environmental language and decide to formally re-learn the HL as adults in a classroom setting. Polinsky asks whether heritage speakers make better L3 learners of their latent HL than speakers who learn this same language as a late L2. If they show considerable advantages, then we may conclude that a latent, non-used native language is never lost and, in cases of renewed contact, this language is reactivated, not newly learned as an L3. If, on the other hand, this population evidences performance similar to that of “traditional” late L2 learners, we may conclude that a language that has not fully stabilized in childhood must be relearned as an L3. Polinsky concludes that “heritage-speakers-turned-learners” may not reactivate their whole HL in cases of renewed contact; instead, they have to relearn certain areas of language structure, particularly morphosyntax. These speakers may therefore show only “selective advantages in mastering the phonetics and phonology of their L1/L3” (165). Polinsky recognizes, however, that her conclusions are based on limited data, since “the work on re-learning of L1 as L3 is still in its infancy” (165).

A further population that has been a test case for this question of “reactivation-versus-relearning” are internationally adopted children. These are children who are adopted by families that live outside the child’s country of birth and move to their new homeland, where they are completely deprived from their L1 from this moment on. As a result, these speakers are posited to effectively lose their L1 and replace it with their L2 (Reference Pallier, Dehaene and PolinePallier et al., 2003; Reference Ventureyra, Pallier and YooVentureyra et al., 2004). Often, they enroll in language courses to relearn their native language when they are adults. Currently, there is no consensus on the question of whether the L1 is effectively erased from the speakers’ brain (as suggested by, for instance, Reference Pallier, Dehaene and PolinePallier and colleagues [2003]) or if they maintain L1 remnants that are activated when the speakers are re-exposed to this language. Research with international adoptees show that there are indeed remnants at least at the phonetic level, which may boost the reactivation of the attrited L1 (Reference Hyltenstam, Bylund, Abrahansson and ParkHyltenstam et al., 2009; Reference ParkPark, 2015; Reference Choi, Broersma and CutlerChoi et al., 2017). The prediction arising from this observation is that the re-exposure to an apparently lost native language will lead to a learning process that differs from traditional non-native (L2/L3) acquisition.

Moving this discussion to the population of (double) returnee bilinguals, again, the research addressing questions of relearning and reactivation is scarce. We selected two studies on Turkish returnees from Germany in an attempt to discuss this topic, even though indirectly. The first study is by Reference Treffers-Daller, Daller, Furman and RothmanTreffers-Daller and colleagues (2016), who analyzed a property that is challenging in the acquisition of Turkish by non-native speakers, namely collocations and fixed expressions (involving yap- and et- “to do”), and asked if bilingual returnees have difficulties in fully mastering this property after returning to Turkey. The results show that the returnees did not use target-like collocations in their HL Turkish before or right after their return but developed native-like knowledge within seven years of re-immersion in Turkey. Even though they do not compare the target group with L2 learners of Turkish, they conclude that the returnees activated their native language’s grammatical system with increasing input, which is distinct from that of a non-native language. Overall, the finding in this study contradicts the idea that some properties of a native language that are latent or not fully stabilized may be relearned as a non-native language/L3 in a case of increased input. However, there is also evidence that not all linguistic properties of a HL converge toward the monolingual/homeland norm, even several years after the return to the country of origin. This is shown by Reference Kaya-Soykan, Antonova-Unlu and Sagin-SimsekKaya-Soykan and colleagues (2020) in a study involving fifteen Turkish returnees. They analyzed the participants’ production and perception of evidentiality markers in their heritage Turkish eleven years after their return from Germany. The authors concluded that even after “many years of residing in Turkey the language behaviour of the returnee participants still differed from monolingual Turkish speakers” (16). Of course, this conclusion does not imply that the HL is like an L3 in this domain of evidentiality markers, but it hints that there are properties of a native language that have to be fully stabilized during the optimal phase in order for it to be acquired.

In addition to the development of the HL upon return, we may also look at situations of double return. Recall that, in this case, bilingual returnees move to the homeland, typically in childhood, and spend a period of time in the homeland environment, where they lose contact with the L2. After this time in the homeland, the speakers move back to the country of migration and are re-immersed in the dominant L2 environment. This situation was investigated by Reference Flores, Schmid and KöpkeFlores (2019) in a case study on a bilingual Portuguese–German speaker who moved to Portugal at the age of nine and went back to Germany after a four-year stay in Portugal. During her stay in Portugal, considerable effects of attrition were detected at various levels of morphosyntactic knowledge; eleven months after being re-exposed to German, the rate of attrition in case, gender, and plural marking decreased significantly. The author argues that re-stabilization of native linguistic knowledge occurred, which is in line with the idea that a latent language system is reactivated shortly after the speaker is immersed in the target language’s environment.

15.3.3 Scenario 3: L3 Development after Return and the Role of the Dominant Language Environment – A Contribution to the Theoretical Discussion of L3 Acquisition Models

The third and final scenario we would like to consider is how the other languages (L1 or L2 or 2L1) of a returnee may influence L3 development/attrition upon return to the homeland. In Section 15.3.1, we discussed the trajectories of L3 attrition (with the limited evidence available in the literature) and described potential factors that may affect this process in light of findings from L2 attrition literature. What we did not consider, however, is the potential crosslinguistic influence that may occur from the L1/2L1 or L2 to the L3. For example, let us illustrate a hypothetical case of Japanese–English bilingual children who moved to France and acquired French as an L3 in the community. When these children move back to Japan, some may receive the majority of their input in Japanese by entering a Japanese school system, while others may enroll their children in English as a medium (EMI) schools, thereby getting ample English exposure in school. Given that French is not widely spoken in Japan, it is likely that under this scenario, the children’s L3 French will undergo changes, perhaps as a result of influence from the L1 (Japanese) or the L2 (English). In such cases, what factors may drive the potential effects of multilingual crosslinguistic influence? Does dominance or linguistic structure play any role? We would like to review some models and studies from L3 acquisition literature for insight into this line of inquiry.

Several formal models have been proposed in the L3 acquisition literature to explain the source of CLI and/or transfer (for discussion on distinctions between CLI and transfer, see Reference Rothman, González Alonso and Puig-MayencoRothman et al., 2019; Reference Schwartz and SprouseSchwartz & Sprouse, 2021; for a detailed overview of these models, see Chapter 1 of this volume; but we will use the term “influence” to include all instances of effects from one language to the other). These models, however, mainly focus on the initial stages of sequential L3 acquisition. One of the earlier hypothesis established in the field, the L2 Status Factor Hypothesis (L2SF) (Reference Bardel, Falk, Cabrelli Amaro, Flynn and RothmanBardel & Falk, 2012), assumes that the individual properties of the L2 will influence the L3. Following Reference ParadisParadis (2004), the authors assume that this is because the same memory system, namely, declarative memory is used to sustain explicit knowledge of grammar in the L2 and L3, while speakers use procedural memory to sustain implicit or automatized knowledge of their native grammar. Due to the fact that L2SF does not explicitly state when influence can occur and also confers maturational constraints (i.e., focuses on adult L2/L3 learners), it is uncertain whether it can be applied to predict the nature of CLI in the child returnee population. However, if we were to follow this hypothesis, we would expect syntactic properties of their L2 English to influence their L3 French, regardless of whether they are more dominant (both in terms of proficiency and exposure) in their L2 English or L1 Japanese.

While the L2 Status Factor Model focuses on the sequence of acquisition, the Typological Primacy Model (TPM) (Reference RothmanRothman, 2011, Reference Rothman2015; Reference Rothman, González Alonso and Puig-MayencoRothman et al., 2019) predicts that the structural similarity determines the source of (full) transfer to the L3. The idea here is that, in the initial stages of L3 exposure, linguistic information such as lexicon, phonology, morphology, and surface syntactic structures in the L3 is assessed by the parser against both L1 and L2 grammars. The parser determines the grammar that is holistically closest (i.e., structurally similar) to the L3 grammar and thus is chosen as the best candidate to be transferred onto the L3. Although the TPM restricts its prediction to L3 initial stages, Reference González Alonso and RothmanGonzález Alonso and Rothman (2017) call for the need to examine whether models of L3 acquisition can be applied to developmental stages of L3 interlanguage grammar.

An interesting piece of evidence that aligns with the TPM in the developmental trajectories of an L3 comes from Reference HoppHopp (2019), who tested the applicability of L3 acquisition models to developmental stages in a child population by administering L3 English sentence repetition and oral production tasks in Turkish–German heritage speakers. These children were already learning English as a L3 (once a week) from grade 1 and were tested longitudinally over time, at the end of grade 3 and the end of grade 4 (one year in between). The results showed that, for both sentence repetition and oral production tasks, Turkish–German heritage speakers had greater difficulty (compared to the German “monolingual” controls who were also learning English) with linguistic properties that are dissimilar between German and English, while in terms of shared properties, they showed comparable performance to the controls. Crucially, properties that are different between Turkish and German/English showed no signs of influence in L3 English. Hopp’s finding suggests that child heritage speakers holistically transferred the structurally similar language (German) to their L3 (English), which is line with the TPM. One important aspect that Hopp points out, nonetheless, is that it is impossible to tease apart the effect of dominance from typological proximity since the heritage speakers in his study were more dominant in the majority language, German, rather than their HL, Turkish.

In fact, studies that tested the role of dominance in L3 influence are largely inconclusive (Reference Fallah, Jabbari and FazilatfarFallah et al., 2016; Reference Fallah and JabbariFallah & Jabbari, 2018; Reference Lloyd-Smith, Gyllstad, Kupisch and QuagliaLloyd-Smith et al., 2018; Reference Puig-Mayenco, Miller, Rothman, Cho, Iverson, Judy, Leal and ShimanskayaPuig-Mayenco et al., 2018, Reference Puig-Mayenco, Rothman and Tubau2020). For instance, Reference Fallah and JabbariFallah and Jabbari (2018) compared L3 English performance of three groups of bilingual young adolescents in their initial stages of L3 acquisition: (1) Mazandarani–Persian bilinguals who are dominant in their L1 Mazandarani, (2) Mazandarani–Persian bilinguals who are dominant in their L2 Persian, and (3) Persian–Mazandarani bilinguals who are dominant in their L1 Persian. The results from a grammaticality judgment task and elicited production task on attributive adjectives showed that language dominance (measured by quantity of exposure) was the only factor that sufficiently explained the observed differences in performance among the three groups. That is, group (1), who is more dominant in Mazandarani, accepted and produced more attributive adjectives in prenominal position, while groups (2) and (3), who are more dominant in Persian, allowed more attributive adjectives in postnominal position. However, the authors do point out that it is difficult to determine which language of the two (Mazandarani–Persian) are more similar to English, rendering it difficult to make strong predictions about the role of structural proximity on L3 transfer, posited by the TPM (and other models such as the Cumulative Enhancement Model [Reference Flynn, Foley and VinnitskayaFlynn et al., 2004; Reference Berkes and FlynnBerkes & Flynn, 2012]).

As shown in the studies highlighted, it appears to be extremely difficult to tease apart the influence of external or participant-related factors such as dominance or proficiency (for literature on effects of proficiency, see Reference Lloyd-Smith, Gyllstad, Kupisch and QuagliaLloyd-Smith, 2018) from internal structures of the language on L3 acquisition/development. Moreover, to understand the full picture of how CLI is manifested at the initial stages of exposure to L3 and how this may or may not carry over to later stages of learning or acquisition, there is a need “to start data collection at the initial stages and track these same L3 learners over developmentally long periods of time” (Reference González Alonso and RothmanGonzález Alonso & Rothman, 2017: 689). Although limited, there is some work that suggests that factors such as language dominance affect the rate of L3 development past the initial stages of L3 influence (Reference Puig-Mayenco, Rothman and TubauPuig-Mayenco et al., 2020).

We propose that returnees will be an excellent sample to solve these aforementioned issues. First, attrition studies on returnees form one of the few areas of research in which a longitudinal approach is widely adopted, mostly due to the fact that it is crucial to establish a baseline at the onset of their return to pinpoint the changes at the individual level that occur upon linguistic transition. Second, by tracking the development of their L3 from the moment of arrival to the host country to several years after their return to the home country, we will be able to precisely measure how the change in language dominance affects manifestations of L3 CLI. Going back to the Japanese–English–French returnee example, if typological proximity is the driving force of L3 influence at both initial and developmental stages, then it is predicted that English will always influence French, regardless of the changes in language environment. In contrast, if dominance is the sole or overriding factor, then we would expect to see influence from English to French while the returnees are living in the host country (since Japanese would hypothetically be only spoken in the family unit) and, crucially, there should be a gradual shift in the source of influence from L2 English to L1 Japanese (on L3 French) once the returnees move back to Japan. Alternatively, it could be the combination of both of these factors – for instance, Reference Puig-Mayenco, Rothman and TubauPuig-Mayenco and colleagues (2020) found initial L3 influence from a structurally similar language, followed by an effect of dominance in the developmental stages. The major challenge with such an experimental design, however, is to test children immediately after their arrival to the host country and track them longitudinally until they are back for some time in the home country. Such studies would span over a period of at least three to four years, which is largely impractical and costly. However, we believe that longitudinal studies, coupled with such an interesting and unique population, will provide further insights into how an L3 is acquired and how it may interact with L1 and L2. As acknowledged by Reference Bardovi-Harlig and StringerBardovi-Harlig and Stringer (2010), there are several methodological constraints on conducting proper research on L2 attrition in the context of remigration. As has been made clear in this chapter, these constraints are even bigger in research on L3 attrition.