Can prosody encode recursive embedding? Children's realizations of complex NPs in Japanese

Area of Science:

• Developmental Linguistics
• Psycholinguistics
• Phonetics

Background:

• Recursive noun phrases (NPs) are challenging linguistic structures that emerge late in development.
• Japanese syntax is marked by prosodic features like downstep and metrical boost.
• Understanding the role of prosody in acquiring complex syntax is crucial.

Purpose of the Study:

• To compare prosodic and syntactic abilities in Japanese children and adults regarding recursive NPs.
• To investigate the acquisition of lexical prosody, downstep, and metrical boost in relation to complex NPs.
• To determine if prosody aids in the development of recursive phrase production in children.

Main Methods:

• Elicited imitation task administered to 5- and 6-year-old Japanese children (n=28) and adults (n=10).
• Analysis focused on the production of lexical prosody, downstep, and metrical boost.
• Correlation analysis between prosodic features and the ability to produce recursive possessives.

Main Results:

• Children acquired lexical prosody but showed variation in metrical boost, a key differentiator for recursive NPs.
• Downstep was established in children, but metrical boost exhibited interspeaker variability, also present in adults.
• Adult speech demonstrated unreliability in prosodic encoding of syntax, contrary to prior findings.
• Metrical boost magnitude did not correlate with children's recursive possessive production.

Conclusions:

• Japanese children acquire foundational prosodic elements necessary for complex syntax.
• Prosodic marking of syntax, specifically metrical boost, is variable in both children and adults, suggesting general unreliability.
• Prosody does not appear to facilitate the bootstrapping of recursive phrase production in young Japanese speakers.