Markedness and the grammar in lexical diffusion of fricatives.

This paper examines the contributions of markedness and a child's grammar to the process of lexical diffusion in phonological acquisition. Archival data from 19 preschoolers with functional phonological delays were submitted to descriptive analyses of productive sound change in fricatives. Children's presenting fricative inventory, the fricatives newly learned, and their position of occurrence were varied, with word frequency and neighbourhood density measured. Results indicated that lexical diffusion of fricatives occurred differentially by word position. Positional, featural and structural markedness further converged such that change in unmarked structure of any type was implemented in low frequency words. A child's presenting fricative inventory was not directly affiliated with systematic patterns of diffusion. These results have clinical applications for the evaluation of productive sound change and theoretical implications for deterministic models of lexical diffusion and processing models of word recognition.