Assessing the functional adequacy of children's phonological systems

Thesis from Leicester PolytechnicThis study has developed the idea of assessing the functional adequacy of children's phonological systems which are restricted in terns of their contrastive potential. A phonological system is considered functionally adequate if it differentiates between the lexical items in a lexical system which is its function to support. Functional inadequacy resulting from the loss/absence of contrasts in a phonological system is reflected in the presence of hamophony in a lexical system. The concepts and measures of Functional loss (FIDSS) and Index of Multiple Honophony (IMH) have been developed to gauge the potential functional inadequacies of restricted phonological systems. The absence of contrasts from children's phonological systems can be described in terms of phonological processes. Phonological processes have been observed to operate one at a time on a word or in canbinations. It has been shown in this study that combinations of two processes can enter into relationships which result in predictable potential homophony in a lexical system and the ordering of these processes in combinations can be critical for the . occurrence of homophony. FLOSS-values and IMH have been calculated for a selection of phonological processes commonly found to operate in the speech of young normal children and children with disordered phonologies, on the basis of a sample of common vocabulary of normal children. These values have provided a means of testing several hypotheses about the process relationships and functional adequacy put forward in the theoretical model. It has also been argued that the FIDSS-values and the IMH obtained can provide guidelines in the prioritization of treatment goals in the clinical management of phonological disability in children. Suggestions for such guidelines have been put forward on the basis of the results. While this study is essentially a clinically-oriented one, the model developed is considered valid for the study of the functional adequacy of any phonological system which is restricted in terms of its contrastive potential