Does a multilingual person have full control over the language in which he or she communicates?

The BCBL, in collaboration with the University of York, has explored the interaction between different languages in trilingual people.

The studies were carried out on different groups speaking Spanish, Basque and English in Donostia, and English, French and Spanish in the United Kingdom.

The research reveals that when speaking in a second language, the non-native language is more likely to interfere in the vocabulary than the dominant one.

It is estimated that a quarter of the European population can speak three or more languages, but how do these interact in a multilingual person? Which language is more likely to interfere with vocabulary during a conversation in a different language? Do these people have the ability to control 100% of the language they speak without making a mistake?

A new study led by the Basque Center on Cognition, Brain and Language (BCBL) and the University of York (UK) has explored these questions in two different groups of trilingual people: one in Donostia that spoke Spanish, Basque and English, and a second in York that spoke English, French and Spanish.

“Our idea was to contrast the results with different language combinations, and in both studies we found the same thing: there is a greater probability that the less dominant language, and not the mother tongue, interferes with our vocabulary when we speak in our second language,” explains Clara Martin, an Ikerbasque researcher at BCBL.

To do this, the research teams tested the abilities of the trilingual volunteers through a series of images displayed on a screen. The participants had to reproduce what was displayed in the correct language.

For example, when they saw an “apple” with the Basque flag, they had to say the word in Basque. To complicate the task, the photographs were displayed for short periods of time.

Afterwards, they studied which language interfered most with the use of the second language; in the case of the BCBL group, Basque. “We presented them with different images at a very fast pace, to provoke failure, and they had to describe them in Basque. Few errors occurred, but in most cases the language that interfered most was English and not the native language, Spanish”, adds the expert.

Inhibition theory

The results of the joint work by BCBL and the University of York confirm the theory that the brain of a trilingual person is capable of inhibiting the native language to ensure correct communication in their second language, but that they have more difficulty controlling their third linguistic competence.

“This study shows that simply knowing words in a language may not be enough to ensure fluent communication. It is also crucial to find the right words in the right language at the right time and to avoid interference. Trilinguals may have less experience, or may be worse, at inhibiting a non-native language and may therefore experience more errors,” concludes Dr Angela De Bruin, from the UK University’s Department of Psychology.

The research therefore highlights the importance of better understanding the relationship between languages acquired during childhood and adolescence and how fluent communication in these languages may not only require a certain level of linguistic knowledge, but also efficient control over the other languages acquired.

The results of the study have been published in the Journal of Memory and Language and have also been published on the University of York website.