Developmental disfluency and emerging grammar. I. Disfluency characteristics in early syntactic utterances

Area of Science:

• Developmental Psychology
• Linguistics
• Speech-Language Pathology

Background:

• Understanding typical speech development is crucial for identifying potential communication disorders.
• Developmental disfluency is a normal aspect of early language acquisition.
• Previous research has explored disfluency but lacked detailed analysis across specific language development stages.

Purpose of the Study:

• To analyze the occurrence and types of developmental disfluency in nonstuttering children.
• To map disfluency profiles across different stages of early language development, specifically Mean Length of Utterance (MLU) levels.
• To investigate the relationship between disfluency patterns and psycholinguistic factors in child language acquisition.

Main Methods:

• Analysis of approximately 47,200 spontaneous utterances from four nonstuttering children.
• Tracking language development from one-word utterances to the emergence of beginning syntax.
• Categorization and computation of disfluency types and frequencies at four distinct MLU levels for each child.

Main Results:

• Individual disfluency profiles varied among the participating children.
• Systematic changes in disfluency frequency and distribution were observed as children progressed through MLU levels.
• These changes correlated with psycholinguistic features such as discourse, imitation, and increasing grammatical complexity.

Conclusions:

• Developmental disfluency is dynamic and evolves predictably with language complexity.
• The study provides a detailed normative profile of disfluency in early child language.
• Understanding these typical disfluency patterns is essential for differentiating normal development from potential stuttering.