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Are bilingual children at greater risk of stammering?

Corinne Moffatt | 01.12.2008

Are bilingual children more likely to stammer? Corinne Moffatt considers a new research paper.

I was delighted to be invited to review this recently published research: P. Howell et al, 'The effects of bilingualism on stuttering during late childhood'. Having worked for many years as a dysfluency specialist with children in the multi-cultural inner London Borough of Tower Hamlets, the challenge of providing a high quality service to children and families who are bilingual is central to my everyday work. Parents often say they believe that their child is stuttering because they are speaking more than one language. Until now, I have felt quite confident in being able to say that there is no evidence to support this view, but it seems that this research may be providing just that.

The aim of the study was to examine the stuttering of children who speak an alternative language to English and the possible effects of being bilingual on dysfluency. The sample comprised 317 children who stutter aged 8-10 years who had first presented at a speech and language therapy clinic at this age. These were divided into a group who had been spoken to at home primarily in a language other than English before starting school; a group who had grown up being exposed to another language and English; and a group of children who only spoke English. There was a control group of children of the same age who did not stutter. All subjects were recruited from the Greater London area. Data was collected through interviews with the child's caregiver about their language background, speech recordings and measurement with the stuttering severity instrument (SSI-3) and results of the SATs for Key Stage One (age 7) and Key Stage Two (age 11). Most children's speech was re-assessed after they had turned 12 years of age. The results of the research indicated that the children who had grown up speaking two languages were more prone to starting to stutter than the children who had grown up speaking just one, and had a lower chance of recovery. SATs results for all groups were similar.

The researchers have clearly worked hard to obtain a sample of this size and to find a sufficient number of children who have not been exposed to English until starting school. However, examining the size of the different groups, it could be argued that the sample was still relatively small for the bilingual children.

One factor which is of particular interest is the age at which the children started to stutter. For all the groups, the reported average age of starting to stutter was between four and five years which is relatively late (around three years is more typical). This later onset certainly matches my experience in clinic. Many of the children I see from both bilingual and monolingual backgrounds are delayed in their language development at a pre-school age which unfortunately is not unusual in areas of high socio-economic deprivation. It would follow that a child delayed in language development may start to stutter later. In the absence of information regarding their early language acquisition, it is unclear whether the stuttering risk factor for children in the study was being bilingual, having delayed language development or the two in combination.

Many children in the study presented at clinic a long time after they started to stutter and so, without help, were at greater risk of their stuttering persisting. In Tower Hamlets we find that children from families for whom English is not a first language tend to be identified and referred late and therefore are less likely to benefit from early intervention. It would therefore be likely that a disproportionately large number of older children who stutter would be from a bilingual background. It is widely understood that 1% of the population stutter across the world but is it the case that there are more children who stutter in later childhood in countries where bilingualism is the norm than in monolingual cultures?

As for the message to give to parents, I will be exercising more caution in telling parents that there is no evidence that bilingual children are more at risk of stuttering. However, I will not be advising them to speak only one language as I believe that interfering with a child's natural language environment can have far reaching social and emotional consequences. In my view, the role of the speech and language therapist is to adapt any treatment to meet the child's fluency and linguistic needs.

Reference: Howell et al. (2008), The effects of bilingualism on stuttering during late childhood, Arch Dis Child. doi:10.1136/adc.2007.134114

Corinne Moffatt is a Specialist Speech and Language Therapist at Tower Hamlets PCT, London

From the Winter 2008 issue of 'Speaking Out', page 16.