English compound versus non-compound noun phrases in discourse: an acoustic and perceptual study

The aim of the present paper is to describe, in acoustic and perceptual terms, the prosodic pattern distinguishing English compound and non-compound noun phrases, and to determine how information structure and position affect the production and perception of the two forms. The study is based on the performance of ten English-speaking subjects (five speakers and five listeners). The test utterances were three minimal-pair noun phrases of two constituents, excised from conversational readings. These were analyzed acoustically, and submitted to the listeners for semantic identification. The results indicate that the distinction, when effective, lies primarily in the different prominence pattern: a sequence of an accented constituent followed by an unaccented one in compounds, and of two accented constituents (the second heard as stronger than the first) in non-compounds. It is also based on a different degree of internal cohesion, stronger in compounds and weaker in non-compounds. F0, associated or trading with intensity, has proved to be the main cue to this distinction--more than duration, the major differentiating parameter in production. When an item is excised from the context, the perception of the intended category depends heavily on the communicative importance it had in the discourse. This means that information structure, through its effects on accentuation, becomes the determining factor in the perception of the distinction. The distinctive accentual pattern weakens or is completely neutralized when the test items convey old information. The degree of deaccentuation also seems to be affected by an immediately following focus, and, to a certain extent, by position. The data are viewed in the framework of speaker-listener interaction, and it is argued that deaccentuation, as well as accentuation, can have a communicative function.