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.

In two experiments, we examined the hypothesis that bilingual speakers modulate their cognitive control settings dynamically in the presence of different interlocutors, and this can be captured through performance on a non-linguistic attention task. We introduced Malayalam–English bilinguals to interlocutors with varying L2 dominance through a pre-experiment familiarisation and interaction phase. Later, participants did the Flanker task while the interlocutors appeared before each trial. While in experiment one participants did the Flanker task with equal distribution of trials, in experiment two we manipulated the monitoring demands by changing the frequency of trials. Results showed that high-L2 proficient bilinguals had lower conflict effect on the Flanker task in the presence of balanced interlocutors in both the experiments. The results provide strong evidence of dynamic adaptation of control settings in bilinguals with regard to different passively present interlocutors. The results further extend the predictions of the adaptive control hypothesis with novel manipulation.

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.

Recent theories propose that language-switching in bilinguals influences executive control. We investigated whether switching behaviour, shaped by the bilingual's interactional context as well as personal preferences impacted attentional control. We compared four groups – (i) Edinburgh monolinguals, (ii) Edinburgh non-switching late bilinguals, (iii) Edinburgh non-switching early bilinguals, and (iv) Singapore switching early bilinguals – on two tasks of attentional control. Effects of interactional context were observed, with Singapore bilinguals performing better on conflict resolution in the Attention Network Task and Edinburgh late bilinguals on attentional switching in the Elevator reversal (Test of Everyday Attention) subtest. Our results suggest that the interactional context of bilinguals could impact attentional control differently.