Acquisition of frication by severely hearing-impaired children.
The ability of severely deaf school children to master fricative production and the fricative-affricate distinction was studied over a period of 6 months. The children were given daily speech therapy and half of them received, in addition, visual feedback from a microprocessor-based speech training aid - the 'Fricative and Timing Aid'. The speech of a third group of children, who received no training from us, was also monitored. Results were analysed in terms of the acquisition of fricatives and affricates, and of their position in a word. Results yielded by perceptual tests showed a substantial increase in the intelligibility of all trained children for almost all phonemes at the end of the training programme. Retention scores, i.e. intelligibility scores obtained by re-testing the children after a 2-moth period of non-practice, showed that practically no forgetting of articulatory skills occurred during this interval. Comparisons between children trained with or without visual feedback in general showed no difference between them; however, the former were more intelligible when producing affricates. No improvement in intelligibility was found when no systematic speech training was available. It was concluded that while frication may not be acquired spontaneously, it is a task within the reach of severely deaf children when adequately trained.