Error patterns observed during the acquisition of speech and language are often thought to arise from higher level cognitive and linguistic processes. The extent to which these patterns are influenced by features of the motor system itself is unknown. One frequently observed error type common to young children who are typically developing and older children with speech disorders is the omission of unstressed syllables, particularly those in initial position. Such syllable omissions may be complicit in the often observed difficulties children have with the acquisition of grammatical morphology, since, in English, grammatical morphemes are unstressed. Perception- and production-based accounts have been proposed as explanations for these potentially related error patterns. On the production side, it may be that preferred movement templates or parameters lead to, or interact with, the proclivity to produce stressed initial syllables. Given the paucity of direct data, however, such explanations remain conjectural. The central aim of the present proposal is to delineate parameters and underlying patterning of movement across stress, serial position, and morphological contexts. This aim has implications, both for providing direct evidence regarding interactions between physiological and linguistic factors and for designing appropriate treatment programs for children with speech disorders. Specifically, these experiments will acquire kinematic and acoustic data from young children who are typically developing, children who are speech disordered, and adult controls. Recordings of oral movement will be obtained while children and adults produce novel words varying in intra- word stress, the serial position of stress, and morphological status. Basic parameters of movement (e.g., displacement, velocity, smoothness, stability) will be measured across ages, disorder conditions, and linguistic contexts. Movement records will also be normalized (i.e., removing the effects of changes in time and amplitude) and underlying movement patterning will be examined across contexts. From these data, hypotheses regarding physiological interactions with suprasegmental and morphological errors may be directly assessed. Further, potential qualitative and quantitative differences in the speech motor systems of children with language disorders may be evaluated.