A Linguistics research team at Bangor University has conducted the world’s first study documenting bilingual language development in an individual with Rett syndrome, a rare genetic condition. The study, published in the journal Clinical Linguistics and Phonetics, shows that an individual with Rett syndrome can develop language skills bilingually.

Rett syndrome is a neurodevelopmental condition, which affects physical and linguistic development. Generally, people with Rett syndrome will show typical development in the first year of life followed by a loss in skills, such as the ability to walk and talk. Some individuals have a type of Rett syndrome which allows them to develop a limited amount of speech, known as the preserved speech variant.

Researchers from the Child Bilingualism Lab used a longitudinal case study design to document the language development of an English-Welsh bilingual with the preserved speech variant of Rett syndrome. The participant demonstrated development in her understanding and production of both English and Welsh over the course of three years.

Rebecca Day, PhD Researcher in Bilingualism at Bangor University and lead author of the study, says: ‘We have heard from bilingual families stating that they have been encouraged to speak only English to their children with Rett syndrome by professionals because of a fear that two languages would be too confusing. This study is an exciting first step in showing families that bilingualism is not harmful to the language development of people with Rett syndrome.’

This new study adds to our understanding of bilingualism in individuals with neurodevelopmental conditions. Previous studies, including those conducted at Bangor University, have found no evidence of a negative effect of bilingualism in other developmental conditions, including Down syndrome and autism.

Dr Eirini Sanoudaki, Reader in Linguistics and Head of the Child Bilingualism Lab, explains: ‘Children with developmental conditions can learn two languages and families should be supported if they wish to bring up their children bilingually. We are delighted to present these positive findings on bilingualism in Rett syndrome, an important breakthrough for children’s rights in bilingual Wales and worldwide.’

The study was funded by the Economic and Social Research Council Welsh Graduate School for the Social Sciences and conducted in the School of Arts, Culture and Language at Bangor University. The publication is available here. An accompanying article in The Conversation is available here.