Children from multilingual families understand sign language better

Children raised in bilingual families respond differently to sign language than those whose parents speak only one language - regardless of whether they have had previous exposure to sign language. A paper on this was published in the journal Neurobiology of Language.

Researchers from the University of London analyzed brain neuron activation patterns in 19 children from monolingual families, 20 children from bilingual families (who heard English and some other language regularly from birth), and 21 children born to deaf mothers - this group was taught English and sign language from infancy. The study found that children from bilingual families had a much more active right brain hemisphere both when they heard someone else's speech and when they perceived sign language.

The scientists concluded that children who are raised in bilingual families develop a heightened sensitivity to language structure. As a result of such exposure, their brains respond to gestures in the same way as to spoken language. Most surprising was the fact that the patterns of neural activity in children who grew up in bilingual environments differed more from similar patterns in children from monolingual families than in those who were taught spoken English and sign language in the home.

“Both spoken and sign languages have a hierarchical structure in which different elements combine to form utterances. Perhaps the structural similarities between spoken and sign language result in a similar activation pattern for both language modes,” explains the findings to Dr. Evelyn Mercure, lead author of the study.

Unimodal bilinguals (those who know two spoken languages) may also be more sensitive to visual features of speech articulation. “Our study contained some characteristic English lip movements often present in natural sign language, so it is possible that the activation [of neural activity] of unimodal bilingual infants for sign language is partly related to the processing of these visual speech cues,” summarizes Evelyn Mercure.

Despite the peculiarities of unimodal bilinguals' brain function, researchers note that it is bimodal bilinguals (who know spoken and sign language English) who outperform children from other groups in general communication skills. This is because children who have a deaf parent have to develop more flexible communication strategies.