The perception of fluent speech.

The perception of fluent speech involves both acoustic-driven and knowledge-driven sources of information. Acoustic sources that directly convey information about higher-order linguistic characteristics include the suprasegmental aspects of speech, associated with the acoustic cues of fundamental frequency, duration, and intensity. From the standpoint of cochlear prostheses, interest in listeners' perception of these suprasegmentals is heightened by the fact that these properties are typically among the best preserved sources of speech information in the sensorineural hearing-impaired. Studies with normal listeners indicate that suprasegmentals provide cues to such linguistic factors as word stress, syntactic structure, and semantic interpretation. In addition, they supply information about many nonlinguistic characteristics of the speaker. Research on knowledge-driven processes indicates that normal listeners utilize knowledge of lexical, syntactic, and semantic constraints of the language to guide the segmentation of speech into word-like units and to select among candidate word choices. These findings are related to research with hearing-impaired listeners and prosthesis testing.