Bound morpheme loss errors in normal and agrammatic speech: one mechanism or two?

Area of Science:

• Linguistics
• Neurolinguistics
• Speech Production

Background:

• Speech errors involving bound morphemes are common in both typical and atypical speech.
• Previous research suggests a single processing deficit may underlie these errors.

Purpose of the Study:

• To investigate whether loss errors in bound morphemes stem from a single processing issue.
• To differentiate between general and agrammatic speech production mechanisms.

Main Methods:

• Analysis of bound morpheme errors in spontaneous speech samples.
• Comparison of error patterns in individuals with agrammatism and unimpaired speakers.

Main Results:

• Two distinct problems identified: impaired access to bound morphemes and a syntactic agreement deficit.
• The bound morpheme access problem is significantly more pronounced in agrammatic speech.
• Base form production is linked to the morpheme access issue.

Conclusions:

• Speech errors are not solely due to one processing problem.
• Agrammatism involves a specific exacerbation of bound morpheme access difficulties.
• Findings have implications for understanding both normal and disordered speech acquisition and processing.