e people with Down syndrome studied, word and phrase endings were better articulated and carried more stress than the initial syllable or the head of the tone group. This is contrary to typical speech in English where the first syllable in a disyllabic word and the initial sentence position carries the higher stress. Syllable deletion is common in the speech of people with Down syndrome and Heselwood, Bray and Crookston have suggested that syllable deletion allows for simplification of the rhythmic structure of the utterance, making the neurophysiological process of speaking easier. Links between production and perception need to be considered as Pettinato and Verhoeven show that perception of weak syllables is problematic in adolescents with Down syndrome.
Dysfluency (stuttering) is the inability to move forward in the utterance because of repetitions of
a sound, syllable or word, prolongations of sounds or of silence and tense pauses (both filled and
unfilled) associated often with obvious struggle to produce the word. The issue of whether the dysfluencies
of people with Down syndrome can be defined as stuttering is unresolved as the definition includes
more than just overt speech behaviours (levels of awareness, anxiety and avoidance form part of the
The literature on dysfluency in people with Down syndrome suggest a much higher incidence than in the general population (47% as against 1%[10,11]). Dysfluency can add to the lack of intelligibility in speakers and adds another level of difficulty in the production of speech by children with Down syndrome. Berstein Ratner suggests that, in typically developing children, dysfluency is related to language processing. As grammatical morphemes are rapidly expanding, children find the processing load significantly higher and a breakdown in fluency can result. Bray, in a study of two young dysfluent children with Down syndrome, found that the dysfluencies did not show a definite relationship to word finding problems and that the nature of the speech output consisted of complex patterns of interjection of sounds, production of non-English sounds (clicks) and, in addition, changes in prosodic features such as increased durations of sounds, sudden pitch changes and numerous filled and unfilled pauses. These speech difficulties were also identified by Heselwood in a young dysfluent man with Down syndrome who used clicks (found in African languages) seemingly as a result of involuntary dorso-velar closure while attempting sonorant productions. This suggests a motor-speech difficulty rather than/ as well as a linguistic programming problem.
What could be applied in intervention?
Making direct connections between theory and practice is complicated by the complexity of the speech problems. Unintelligibility is a problem often mentioned by those who live and work with people with Down syndrome. It is related to both sentence construction and the segmental and suprasegmental levels of speech as well as to the listeners' perception and expectations. It is important therefore to (a) find ways of enhancing the message giving by the person with Down syndrome and (b) improve the 'listening' and awareness of the communication partner. There is also a growing literature showing that cognitive and affective factors have a strong influence on the planning and production of speech. This suggests that a relaxed, at ease, dialogue is far more likely to be understood by both parties than one where one or both partners in the exchange is anxious. The work of Wishart alerts us to the necessity of understanding the learning styles of children with Down syndrome and ensuring that the learning environment is facilitative. In the stuttering literature, the importance of keeping a balance between the child's capacities in language and cognition and the performance demands made on that child is seen as highly significant in maintaining fluency. This is known as The Demands and Capacities model.
Possible approaches to managing speech output difficulties therefore must include:
- A holistic approach which supp