Specific Language Impairment (SLI) in British Sign Language (BSL)

For the past 3 1/2 years City University and DCAL have conducted a research project looking into SLI in signing deaf children. SLI is a term used by teachers, speech and language therapists and professionals working with deaf children to describe children who have problems with learning language despite normal nonverbal IQ (NVIQ), neurological function, motor development, social interaction, no impairments in facial-oral structure and function and normal hearing (Leonard, 1998).

Children with SLI may have problems in one or more area of language. This includes; syntax, phonology, vocabulary, pragmatics, motor skills, memory, and grammar.

Why focus on SLI in sign language?
In the past, studies looking into SLI have excluded deaf children due to their deafness. It was believed that deafness would be a contributory factor in language learning problems. However, if 7% percent of the general, hearing population have been found to have SLI, then this may also be true for the deaf, sign language users’ population. This research looks into whether or not SLI exists in sign language.

The Tests
We use a large battery of tests to evaluate all aspects of a child’s sign language skills. We use the BSL Receptive and Productive tests, the Non-Sign Repetition Test (NSRT) for assessing phonological skills, the British Ability Scales (BAS) to test non-verbal IQ, Semantic fluency, Vocabulary test, Sentence repetition test to evaluate grammar and memory, bead threading test to rule out motor problems and a definitions test which is an extension of the vocabulary test.

Children and Results
We have had 50 children referred to us by both teachers of the deaf and speech and language therapists. We have assessed 30 children and are continuing to assess children. Of these children, we have found that 6% are suspected to have SLI in sign language. This is significant as it similar to the 7% of the general population who have been found to have SLI. As found in spoken language, signing children who have been suspected to have SLI in sign language are an extremely heterogeneous group. Their language difficulties varies, they have difficulties with different aspects of language. No two children are the same.

The characteristics of SLI in deaf signers, despite the modality difference, are strikingly similar to those found for hearing children with mixed strengths and weaknesses across different areas of language structure and use. Some children had particular problems with comprehension, others with expressive difficulties, and some with problems in all areas of language.

The project has now come to an end, however, we are continuing to write up the results for publication and sharing thie information with professionals. If you have any concerns about a child, you can contact Dr. Rosalind Herman - a speech and language specialist and lecturer at City University.

Email: R.C.Herman@city.ac.uk

If you wish for your child to have an independent assessment, you can contact the Compass Centre at City University. Parents and professionals working with deaf children can refer children to the Compass Centre directly.

Bethan Lewis - Senior Clinic Administrator
Department of Language and Communication Science
City University London
Northampton Square
London EC1V 0HB

Tel: 020 7040 8288
Fax: 020 7040 8577
Email: compasscentre@city.ac.uk
Website: www.city.ac.uk/lcs/compass/signassessment/signAssessment.html

Project publications
Mason, K., Rowley, K., Marshall, C.R., Atkinson, J.R., Herman, R., Woll, B., & MOrgan, G. (2010). Identifying Specific Language Impairment in Deaf children acquiring British Sign Language: Implications for theory and practice. British Journal of Developmental Psychology, Volume 28, Part 1, March 2010.

There will be more publications this year. Please continue to check this webpage for any updates.

In addition, we have created a factsheet about SLI in collaboration with the National Deaf Children's Society (NDCS); please contact them for further information.

Workshop/training
We hope to set up a training/workshop day towards the end of thsi year that will focus on developmental language impairments