INTRODUCTION T    by normally developing children is an area that has received increasing attention in the past decade, but the substitutions that characterize children’s speech remain largely undocumented. Looking at adult phonological substitutions1, we fi nd that the range of normal substitutions is very wide, but clear. ere is every reason to believe that we should fi nd at least that same range in normal children. But existing descriptions of children’s speech show only a small sample of the systems and substitutions that could occur, and little eff ort has been made to determine whether children’s limitations and substitutions are coextensive with those of adult languages.2