Despite the multifactorial space of language experience in which people continuously vary, bilinguals are often dichotomized into ostensibly homogeneous groups. The timing of language exposure (age of acquisition) to a second language (L2) is one well-studied construct that is known to impact language processing, cognitive processing, and brain organization, but recent work shows that current language exposure is also a crucial determinant in these domains. Critically, many indices of bilingual experience are inherently subjective and based on self-report questionnaires. Such measures have been criticized in favor of objective measures of language ability (e.g., naming ability or verbal fluency). Here, we estimate the bilingual experience jointly as a function of multiple continuous aspects of experience, including the timing of language exposure, the amount of L2 exposure across communicative contexts, and language entropy (a flexible measure of language balance) across communicative contexts. The results suggest that current language exposure exhibits distinct but interrelated patterns depending on the socio-experiential context of language usage. They also suggest that, counterintuitively, our sample more accurately self-assesses L2 proficiency than native language proficiency. A precise quantification of the multidimensional nature of bilingualism will enhance the ability of future research to assess language processing, acquisition, and control.

This study examines the variable positioning of a finite adverbial subordinate clause and its main clause with the subordinate clause either preceding or following the main clause in native versus nonnative English. Specifically, we contrast causal, concessive, conditional, and temporal adverbial clauses produced by German and Chinese learners of English with those produced by native speakers. We examined 2,362 attestations from the Chinese and German subsections of the International Corpus of Learner English (Granger, Dagneaux, Meunier, & Paquot, 2009) and from the Louvain Corpus of Native English Essays (Granger, 1998). All instances were annotated for the ordering, the subordinate clause type, the lengths of the main and subordinate clauses, the first language of the speakers, the conjunction used, and the file it originated from (as a proxy for the speaker producing the sentence so as to be able to study individual and lexical variation). The results of a two-step regression modeling protocol suggest that learners behave most nativelike with causal clauses and struggle most with conditional and concessive clauses; in addition, learners make more non-nativelike choices when the main and subordinate clause are of about equal length.

This study investigates the effect of socioeconomic status (SES) as a proxy for input quality, in predicting language proficiency. Different operationalizations of SES are compared, including simple measures (parental education and parental occupation) and complex measures combining two dimensions (among parental education, parental occupation, and deprivation risk). All significantly predict overall English proficiency scores in a diverse group of 5- to 7-year-olds acquiring English and another language. The most informative SES measure in that respect is shown to be a complex measure combining parental education and parental occupation. That measure is used in a second set of analyses showing that different aspects of language are affected differently by variations in SES and in language exposure.

Previous research has suggested that the language development of bilingual children benefits from more exposure and opportunities for language use. Typically, this research has used aggregated measures of exposure and use. The role of specific interlocutors and in particular older siblings has received comparatively little attention. In this study, we examine the impact of having an older sibling on the language environment and language development of a group of 31 bilingual Greek–Dutch toddlers aged 16 to 30 months growing up in the Netherlands. Approximately half (n = 14) of the toddlers had an older sibling. With respect to language environment, toddlers with older siblings were in general found to hear and use more Dutch at home than their first-born peers. There were however no differences between the two groups of toddlers in terms of parental language use. With respect to language development, toddlers with older siblings were found to score higher than first-born peers on measures of Dutch receptive vocabulary, productive vocabulary, and morphosyntactic complexity. For Greek, no such differences were observed. The findings are discussed in light of factors including family constellation, parental language proficiency, bilingual parenting strategies, and the wider sociolinguistic context.

The current study examines how monolingual children and bilingual children with languages that are orthotactically similar and dissimilar learn novel words depending on their characteristics. We contrasted word learning for words that violate or respect the orthotactic legality of bilinguals’ languages investigating the impact of the similarity between those two languages. In Experiment 1, three groups of children around the age of 12 were tested: monolinguals, Spanish–Basque bilinguals (orthotactically dissimilar languages), and Spanish–Catalan bilinguals (orthotactically similar languages). After an initial word-learning phase, they were tested in a recognition task. While Spanish monolinguals and Spanish–Catalan bilingual children recognized illegal words worse than legal words, Spanish–Basque bilingual children showed equal performance in learning illegal and legal patterns. In Experiment 2, a replication study was conducted with two new groups of Spanish–Basque children (one group with high Basque proficiency and one group with a lower proficiency) and results indicated that the effects were not driven by the proficiency in the second language, as a similar performance on legal and illegal patterns was observed in both groups. These findings suggest that word learning is not affected by bilingualism as such, but rather depends on the specific language combinations spoken by the bilinguals.

Bilingual children may choose to reply to utterances in one language with another language. This behavior, which we call interspeaker code-switching, reportedly varies in frequency across children yet the sources of such variation are not well understood. While its use has been linked to variation in proficiency both concurrently and longitudinally, quantitative analyses of this relationship are limited. Here we measure frequency of interspeaker code-switching in a new population, French–English bilinguals in France (ages 5–8), using parental report and relate it to children’s self-reported language attitudes and perceptions of dominance, English receptive and expressive vocabulary, and sentence repetition ability. These children use interspeaker code-switching infrequently and nearly exclusively in the direction of French. Use is predicted by children’s expressive lexical and grammatical proficiency but not their attitudes toward English and French and exhibits only a marginally significant relationship with self-reported dominance. It shows a closer relationship with proficiency than other more well studied experience variables such as current exposure and output, especially for children with lesser English use. These results support a strong link between interspeaker code-switching and proficiency but not for children’s attitudes in a context where they are generally favorable.

This study examines whether the foreign language effect mitigates reactions to value-inconsistent sociopolitical content. We examined 69 English–Spanish bilinguals and 31 Spanish–English heritage bilinguals, half of whom did the experiment in their native language and half in their second language. Participants were administered a survey in which trial emotiveness was manipulated by using the quantifiers some and all (e.g., Some Trump supporters are racists vs. All Trump supporters are racists). The some-types (n = 30) served as a baseline for the all-types (n = 30). After each target, participants rated their willingness to be prosocial (e.g., holding the door for a stranger) on a scale of 1–7, 1 being totally agree and 7 being totally disagree. Our results suggest that processing emotional information in a second language is less emotional than in a first language and that such a decrease in emotionality results in the neutralization of offense taken. However, individual differences in linguistic profiles across participants, as well as contextual framing, lead to discrete value judgments. Proficiency, learner type, political affiliation, and context type affect willingness to engage in prosocial behavior. As a group, the bilinguals showed no decrease in their willingness to engage in such behaviors, regardless of context type; speakers of higher proficiency and stronger political values increase prosocial sentiment; and lower proficiency and weaker views lead to neutral prosocial sentiment.

Research into nonnative (L2) morphological processing has produced largely conflicting findings. To contribute to the discussions surrounding the contradictory findings in the literature, we examined L2 morphological priming effects along with a transposed-letter (TL) methodology. Critically, we also explored the potential effects of individual differences in the reading networks of L2 speakers using a test battery of reading proficiency. A masked primed lexical decision experiment was carried out in which the same target (e.g., ALLOW) was preceded by a morphological prime (allowable), a TL-within prime (allwoable), an substituted letter (SL)-within prime (allveable), a TL-across prime (alloawble), an SL-across prime (alloimble), or an unrelated prime (believable). The average data yielded morphological priming but no significant TL priming. However, the results of an exploratory analysis of the potential effects of individual differences suggested that individual variability mediated the group-level priming patterns in L2 speakers. TL-within and TL-across priming effects were obtained only when the performance of participants on nonword reading was considered, while the magnitude of the morphological priming effects diminished as the knowledge of vocabulary expanded. The results highlight the importance of considering individual differences while testing L2 populations.

In studies of bilingual word recognition with masked priming, first language (L1) primes activate their second language (L2) translation equivalents in lexical decision tasks, but effects in the opposite direction are weaker (Wen & van Heuven, 2017). This study seeks to clarify the relative weight of stimulus-level (frequency) and individual-level (L2 proficiency, L2 exposure/use) factors in the emergence of asymmetrical priming effects. We offer the first data set where L2 proficiency and L1/L2 exposure/use are simultaneously investigated as continuous variables, along with word frequency. While we replicate the asymmetry in priming effects, our data provide useful insights into the factors driving L2–L1 priming. These fall almost exclusively under the category of stimulus-level factors, with L2 exposure/use being the only experiential variable to show considerable influence, although complex interactions involving L2 proficiency and word frequency are also present. We discuss the implications of these results for models of bilingual lexical processing and for the appropriate measurement of experiential factors in this type of research.

Native (L1) and nonnative (L2) speakers sometimes misinterpret temporarily ambiguous sentences like “When Mary dressed the baby laughed happily.” Recent studies suggest that the initially assigned misinterpretation (“Mary dressed the baby”) may persist even after disambiguation, and that L2 speakers may have particular difficulty discarding initial misinterpretations. The present study investigated whether L2 speakers are more persistent with misinterpretation compared with L1 speakers during sentence processing, using the structural priming and eye tracking while reading tasks. In the experiment, participants read prime followed by target sentences. Reading times revealed that unambiguous but not ambiguous prime sentences facilitated processing of the globally correct interpretation of ambiguous target sentences. However, this priming effect was only observed when the prime and target sentence shared the same verb. Comprehension accuracy rates were not significantly influenced by priming effects but did provide evidence of lingering misinterpretation. We did not find significant L1/L2 differences in either priming effects or persistence of misinterpretation. Together, these results suggest that initially assigned misinterpretations linger in both L1 and L2 readers during sentence processing and that L1 and L2 comprehension priming is strongly lexically mediated.

We investigated how operationalizing bilingualism affects the results on a Simon task in a population of monolingual and bilingual native English speakers (N = 166). Bilingualism was measured in different ways within participants, and the measurements were used both as dichotomous and continuous variables. Our results show that the statistical significance and effect size varied across operationalizations. Specifically, the Composite Factor Score (the Language and Social Background Questionnaire’s general score), showed a bilingual disadvantage on reaction times regardless of how it was used (dichotomously or continuously). When dividing participants into monolinguals and bilinguals based on the Nonnative Language Social Use score (a Language and Social Background Questionnaire subscore), differences in accuracy and reaction times were found between the groups, but the Nonnative Language Social Use score did not predict accuracy when used as a continuous variable (only reaction times). Finally, earlier age of acquisition predicted faster reaction times, but only when used on a continuum. Effect sizes were between the small and medium range. No differences on the Simon effect were found. Our results call for cautiousness when comparing studies using different types of measurements, highlight the need for clarity and transparency when describing samples, and stresses the need for more research on the operationalization of bilingualism.

The study of bilingualism has a history that extends from deciphering ancient multilingual texts to mapping the structure of the multilingual brain. The language experiences of individual bilinguals are equally diverse and characterized by unique contexts of acquisition and use that can shape not only sociocultural identity but also cognitive and neural function. Perhaps unsurprisingly, this variability in scholarly perspectives and language experiences has given rise to a range of methods for defining bilingualism. The goal of this article is to initiate a conversation about the utility of a more unified approach to how we think about, study, and measure bilingualism. Using concrete case studies, we illustrate the value of enhancing communication and streamlining terminology across researchers with different methodologies within questions, different questions within domains, and different domains within scientific inquiry. We specifically consider the utility and feasibility of a bilingualism quotient (BQ) construct, discuss the idea of a BQ relative to the well-established intelligence quotient, and include recommendations for next steps. We conclude that though the variability in language backgrounds and approaches to defining bilingualism presents significant challenges, concerted efforts to systematize and synthesize research across the field may enable the construction of a valid and generalizable index of multilingual experience.