Scientists find how bilingual speakers switch between two languages

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Researchers revealed some new knowledge about what happens when people switch between different languages. The study provides new insights into the nature of bilingualism.

The study, published on Monday in the journal Proceedings of the National Academy of Sciences, involved researchers from the New York University (NYU) and San Diego State University. It showed that the neural activity in the process of switching from one language to another, was exclusively associated with disengaging from one language and then engaging with a new one.

This research "unveils for the first time that while disengaging from one language requires some cognitive effort, activating a new language comes relatively cost-free from a neurobiological standpoint," said the paper's senior author Liina Pylkkanen, a professor in NYU's Department of Linguistics and Department of Psychology.

Previous research has linked language switching with increased activity in areas associated with cognitive control in the prefrontal and anterior cingulate cortices. However, as disengaging from the previous language and engaging in a new one usually takes place simultaneously, it remained unknown which part leads the activity.

To solve the problem, the researchers studied bilingual individuals fluent in English and American Sign Language (ASL), who can engage with both languages simultaneously.

American Sign Language (ASL) alphabets. /VCG Photo

"The fact that they can do both at the same time offers a unique opportunity to disentangle engagement and disengagement processes, that is, how they turn languages 'on' and 'off'," said the paper's lead author Esti Blanco-Elorrieta, a postdoctoral candidate at NYU.

The researchers asked the participants to conduct both processes.

From asking the participants to go from producing both languages to producing only one, the researchers viewed the process of "turning off" a language, and they viewed the "turning on" process from a reverse practice.

They used magnetoencephalography and observed bilingual signers/speakers who viewed the same pictures and named them with semantically identical expressions.

The results showed that when bilinguals fluent in English and ASL switched languages, turning a language "off" led to increased activity in cognitive control areas while turning a language "on" was no different than not switching.

In other words, more cognitive work was needed for turning off a language, while little or even no effort in turning on a second language. The results are effective in both spoken and signed languages, according to the study.

They also found that for such speakers, producing two words simultaneously (one sign and one spoken word) was not necessarily more cognitively costly than producing only one.

Rather, producing both at the same time was easier than having to suppress the dominant language (in this case English) in order to name the picture on the screen only in ASL.

Source(s): Xinhua News Agency