Kalveram, K.Th., Natke, U., Sandrieser, P., & Pietrowsky, R. (2001) How linguistically disfluent utterances of young children can be caused by phonologically describable processes. In B. Maassen, W. Hulstijn, R. D. Kent & P. H. H. M. Van Lieshout (Eds.), Speech Motor Control in Normal and Disordered Speech. Proceedings 4th International Speech Motor Conference. Nijmegen, The Netherlands: Uitgeverij Vantilt, 57-60.

Abstract
Vowel onset serves to control vowel length and also to synchronize the serialization of words into temporal strings of syllables. In long stressed syllables this is done via auditory feedback (re-afferent control), while the utterance of short stressed and unstressed syllables is automatized using internal signals (efferent control). Young children's problem when crossing from infantile to adultlike speech then seemingly is to learn to inhibit re-afferent and to apply efferent control of short stressed and unstressed syllables. A multi-level model of speech motor control presented recently (Kalveram, 2001) predicts that the first occurrence of stuttering-like disfluencies should be centered around stressed syllables. Preliminary data of 24 children who stutter aged between 2.8-5.0 years suggest that prolongations of vowel phonation in short stressed syllables indeed could play an important part in the beginning of stuttering.