The structure of /s/-sequences: evidence from a disordered system

This study considers the much-debated markedness and structural status of w ord-initial /s/-sequences in English by examining the development of KR (ma le, age 3;6) who has a phonological disorder. Three points in time are disc ussed: (1) when all initial consonant sequences are reduced to singletons; (2) when only initial /s/-sequences surface correctly; and (3) when all ini tial consonant sequences surface correctly. While these production patterns are common across developing systems, few accounts have addressed them in terms of structure or markedness. Toward that end, it is argued that KR's / s/-sequences surface as ADJUNCTS, rather than complex onsets. This is expla ined within optimality theory, whereby high-ranking markedness constraints prevent complex onsets but not adjuncts. The account offers an explanation for consonant sequence asymmetries within and across grammars, allowing for differing representations for /s/-sequences across speakers and for variat ion exhibited in children's productions. A typology of possible grammars is therefore offered, and clinical implications are considered.