Researchers have argued that grouping heterogeneous linguistic profiles under a dichotomous condition might mask the cognitive effects of bilingualism. The current study used two different analysis approaches (i.e., continuous versus dichotomous) to examine inhibitory control in a sample of 239 young adult bilinguals. Dividing the sample into dichotomous groups based on L2 proficiency (i.e., high-proficient versus low-proficient) and L2 AoA (i.e., early versus late) did not lead to reliable group differences in any of the measurements used. However, the use of a continuous measure revealed that higher L2 proficiency predicted better visual inhibition and earlier L2 AoA was associated with better auditory inhibition. Furthermore, the observed differences were limited to tasks involving stimulus–stimulus competition, but not stimulus–response competition. These findings shed new light on the importance of conceptualising bilingualism as a continuous measure rather than a dichotomous measure and previous research on bilingual performance in different cognitive tasks.

The study explores how native language (L1) lexical access is affected by immersion in a second-language (L2) environment, and by short-term reimmersion in the L1 environment. We compared the L1 picture-naming performance of Polish–English bilinguals living in the UK (migrants) against that of bilinguals living in Poland (controls). Each group was tested twice: the migrants while in the UK (L2 immersion) and after visiting Poland (L1 reimmersion); the controls twice in their L1 environment. Contrary to our expectations, there was no main effect of group, thus suggesting that L2 immersion per se does not impact L1 lexical access. Nevertheless, migrants benefitted from L1 reimmersion by showing faster naming latencies for high-frequency words after a short visit to their home country, probably due to more opportunities to encounter these words. Overall, the study shows that the cognitive system is sensitive to the language environment by quickly adapting the activation level of lexical items.

The current study examined cognitive effects of two pathways of second language (L2) acquisition longitudinally in Chinese speakers learning English in an L2-dominant environment. Thirty-nine participants who attended an intensive 10-week English course (L2-instruction group) were compared to 38 participants who attended regular university courses taught in English (L2-immersion group). Four repeated assessments were conducted over 10 weeks: precourse (baseline) and postcourse assessments, and two interim assessments every 3 weeks. Both groups matched on background variables (e.g., intelligence) and showed comparable cognitive performance in all measures at the baseline. The longitudinal results showed a similar improvement in both groups for most cognitive measures, such as visual and auditory inhibition. The only significant group difference was observed in the auditory inhibition test, where the L2-instruction group outperformed the L2-immersion group. Taken together, our results suggest a specific effect of language experience and an overall effect of linguistic context on cognitive functions.

The current study sought to investigate whether word properties can facilitate the identification of developmental language disorder (DLD) in sequential bilinguals by analyzing properties in nouns and verbs in L2 spontaneous speech as potential DLD markers. Measures of semantic (imageability, concreteness), lexical (frequency, age of acquisition) and phonological (phonological neighbourhood, word length) properties were computed for nouns and verbs produced by 15 sequential bilinguals (5;7) with DLD and 15 age-matched controls with diverse L1 backgrounds. Linear mixed modelling revealed a significant interaction of group and word category on phonological neighbourhood values but no differences across imageability, concreteness, frequency, age of acquisition, and word length measures in spontaneous speech. Outcomes suggest that group-level differences may not be apparent at the word-level, due to the heterogeneous nature of DLD and potential similarities in production during early L2 acquisition.

Studies examining the potential effects of bilingualism on interference suppression show inconsistent results. Our study approaches this topic by distinguishing two potential subcomponents within interference suppression (i.e., Stimulus-Stimulus and Stimulus-Response conflict). We investigated the two subcomponents through their operationalisation in different tasks and examined the role of language proficiency in modulating it. A sample of 111 young adult participants performed four non-linguistic cognitive tasks measuring both visual and auditory domains of cognitive control. Bilinguals outperformed monolinguals in tasks involving Stimulus-Stimulus conflict, but showed comparable performance in tasks involving Stimulus-Response conflict. Specific effects of language proficiency on cognitive control were observed: group differences in auditory inhibition and visual orienting were only observed between high-proficient bilinguals and monolinguals. Taken together, types of conflicts involved in interference tasks and language proficiency could differentially affect performance in monolinguals and bilinguals.

While much of the literature on bilingualism and cognition focuses on group comparisons (monolinguals vs bilinguals or language learners vs controls), here we examine the potential differential effects of intensive language learning on subjects with distinct language experiences and demographic profiles. Using an individual differences approach, we assessed attentional performance from 105 university-educated Gaelic learners aged 21–85. Participants were tested before and after beginner, elementary, and intermediate courses using tasks measuring i.) sustained attention, ii.) inhibition, and iii.) attention switching. We examined the relationship between attentional performance and Gaelic level, previous language experience, gender, and age. Gaelic level predicted attention switching performance: those in higher levels initially outperformed lower levels, however lower levels improved the most. Age also predicted performance: as age increased attention switching decreased. Nevertheless, age did not interact with session for any attentional measure, thus the impact of language learning on cognition was detectable across the lifespan.