This research examines whether a seven-year-old nonverbal boy's comprehension of syntax develops at an accelerated rate following the introduction of speech output through a portable speech synthesizer (VOIS 135). The study was motivated by (1) a general lack of agreement about the relationship of comprehension and production in language acquisition, (2) some child language investigators' claims that--at certain points during the development of language--production precedes and influences comprehension, and (3) the natural experimental condition provided by a nonverbal child who is suddenly given the ability to 'speak' with the help of a portable speech synthesizer. At the beginning of the research period, the child's sentence comprehension was thoroughly assessed with standard and special purpose tests. His production was assessed through analysis of videotaped interactions. The child was then trained to use the synthetic speech device (VOIS 135) over an eight month period. At the end of this period testing of both comprehension and production was repeated to provide a measurement of language growth in each performance mode. The child demonstrated comprehension of concatenated structures and clefts at the end of the research period; this represented a developmental leap from the beginning of the research period when he understood only much simpler structures. During the eight month study, development of comprehension on the lexical level came to an apparent halt. Production results indicated that the child experienced a definite expansion in productive vocabulary and length of utterance during the research period. Observations indicated that the child's pragmatic and discourse skills improved markedly with his use of the speech output device. Factors which might account for developments (or lack of development as in the case of lexical comprehension) are discussed. Clinical implications of improvements in pragmatic and discourse skills through the use of the device are considered along with methodological suggestions for using this study as a pilot for larger research. Conclusions are that: (1) use of the speech synthesizer led the child to listen to utterances as structural wholes; (2) the child became a more active and independent partner in the communication exchange; (3) synthetic speech garnered the child more attention and more opportunities for interaction; (4) synthetic speech gave the subject access to a greater range of communication partners. While the comprehension-production results are interesting, i.e. the child was able to understand structures at a level of unanticipated complexity after being trained to use the speech device, these results do not elucidate the nature of the comprehension-production relationship. Difficulties in interpreting the results of this study underline the need for a coherent theory relating comprehension and production in language development. / Medicine, Faculty of / Audiology and Speech Sciences, School of / Graduate