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

Area of Science:

• Phonological development
• Linguistic markedness
• Speech acquisition

Background:

• Investigates the structural status and markedness of word-initial /s/-sequences in English.
• Examines the developmental trajectory of a child (KR, male, 3;6) with a phonological disorder.
• Addresses common production patterns in developing speech systems that lack structural or markedness explanations.

Observation:

• Documents three stages of KR's speech development regarding initial consonant sequences.
• Stage 1: Reduction of all initial consonant clusters to singletons.
• Stage 2: Correct production of only initial /s/-sequences.
• Stage 3: Correct production of all initial consonant sequences.

Findings:

• Argues that /s/-sequences function as adjuncts, not complex onsets, in KR's grammar.
• Explains this phenomenon using Optimality Theory, where markedness constraints disfavor complex onsets but permit adjuncts.
• Provides an account for asymmetries in consonant sequence production within and across languages.

Implications:

• Explains variation in children's speech productions and differing /s/-sequence representations among speakers.
• Offers a typology of possible phonological grammars related to consonant sequences.
• Considers clinical implications for understanding and treating phonological disorders affecting consonant clusters.