The Adaptive Control Hypothesis and the Control Process Model propose that bilingual language use in different interactional contexts requires control processes that can adapt in different ways to linguistic demands. This study explored the effects of language experience on cognitive flexibility and inhibition among 41 Chinese–English bilingual adults. In particular, it aimed to investigate the relationship between spontaneous language production (i.e., bilingual conversation and narration tasks) and cognitive control. Participants’ inhibitory control and cognitive flexibility efficiency was measured through verbal and spatial Stroop tasks, and a colour-shape switching task. Overall, it showed that frequent practices of intersentential switching in speech production resulted in significant facilitatory effects in both verbal and nonverbal inhibitory control. This study provides new evidence for the importance of bilingual language experience in adaptive cognitive control in naturalistic speech production and furthers our theoretical knowledge of the relationship between the language system and crucial domain-general cognitive processes.

Research examining the cognitive consequences of bilingualism has increasingly relied on continuous measures to capture the degree and nature of bilingual experience, using such variables as proficiency, age of acquisition, and language environments. One such measure, language entropy, indexes the social diversity of contexts in which each language is used. The construct was developed in a particular bilingual context, Montréal, Canada. The present study investigated the extent to which it also applies to a context in which social language use is substantially different from that of Montréal – namely, Toronto, Canada. Following the procedures in the original study, participants were assigned an entropy score and performed the AX-Continuous Performance Task (AX-CPT). Performance was associated with self-rated language proficiency, but unlike the results from Montréal, was not associated with entropy scores. Therefore, differences in the language context influence whether language entropy is related to behavioral performance on a cognitive task.

The multidimensionality of the bilingual experience makes the investigation of bilingualism fascinating but also challenging. Although the literature distinguishes several aspects of bilingualism, the measurement methods and the relationships between these aspects have not been clearly established. In a group of 171 relatively young Polish–English bilinguals living in their first-language environment, this study investigates the relationships between the multiple measures of bilingualism. The study shows that language entropy – an increasingly popular measure of the diversity of language use – reflects a separate aspect of the bilingual experience from language-switching and language-mixing measures. The findings also indicate that language proficiency is not a uniform aspect of the bilingual experience but a complex construct that requires appropriately comprehensive measurements. Collectively, the findings contribute to the discussion on the best practices for quantifying bilingualism.

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.

Bilingual and multilingual individuals exhibit variation in everyday language experience. Studies on bilingualism account for individual differences with measures such as L2 age of acquisition, exposure, or language proficiency, but recent theoretical perspectives posit that the relative balance between the two or more languages throughout daily life (i.e., interactional context) is a crucial determinant for language representation, access, and control. We propose an innovative measure to characterize this construct by using entropy to estimate the social diversity of language use. Language entropy is computed from commonly-collected language history data and generalizes to multilingual communicative contexts. We show how language entropy relates to other indices of bilingual experience and that it predicts self-report L2 outcome measures over and above classic measures of language experience. Thus, we proffer language entropy as a means to characterize individual differences in bilingual (and multilingual) language experience related to the social diversity of language use.