1. How do bilinguals use their languages in different interactional contexts?
We asked Spanish-Basque bilinguals to name pictures in different conditions. In single-language contexts, all pictures were named in the same language. In the voluntary task, bilinguals freely chose a language and switched when convenient. In the cued task, the two languages had to be used interchangeably in response to cues. This required more effort than naming pictures in a single-language context (‘mixing cost’). In contrast, when they could freely use two languages, bilinguals were faster than in a single-language context (‘mixing benefit’). This shows that the effort related to bilingual language control depends on the context. In addition, language choice was highly individual and related to personal preferences as well as speed of lexical access.
2. How does age affect bilingual language control?
Older (mean age: 68) and younger (mean age: 27) Spanish-Basque bilinguals named pictures in voluntary and cued tasks. In the cued task, older adults had more difficulties than younger adults to use two languages and to switch. In the voluntary task, older adults showed a larger switching cost but a comparable mixing benefit. Older bilinguals had greater difficulty using two languages in response to external cues, but freely using two languages might be easier than having to use one language for both age groups.
3. How does bilingual language control relate to cognitive control?
We also assessed whether bilinguals with better inhibition skills were also better at controlling their languages and switching between them. In a large sample of younger adults, we observed some correlations between the ability to switch languages and verbal inhibition. In the older adults, we did not observe this relationship. While there might be some similarities between language control and cognitive control, there are also many differences.
4. What are the neural mechanisms underlying bilingual language control?
Using fMRI, we investigated which brain regions are involved in bilingual language control in single-language contexts versus voluntary contexts. We are currently analysing the results of this project.
