Phonetic detail that distinguishes prefixed from pseudo-prefixed words

Most English prefixes are syllables that can also begin words in which they do not function as a productive prefix. The literature notes a pronunciation difference such that true-prefixes, e.g. /dIs/ in discolour, have a heavier rhythmic beat than pseudo-prefixes, e.g. /dIs/ in discover. When the syllable following dis- or mis- begins with a voiceless stop, there is a clear difference in its VOT, but differences in dis/mis itself are more subtle and have not been systematically measured. Five speakers of Southern British English engaged in 40 scripted dialogues which contained such words in controlled phonetic contexts. Prefixed words were longer up to voicing onset in syllable 2 and had longer and more peripheral [I], longer VOT, and shorter [s] than pseudo-prefixed words. These differences produced distinctive acoustic patterns consistent with the difference in perceived beat. Effects due to nuclear/ postnuclear accent and word frequency were observed, but appear to be secondary to effects of morphological status. We conclude that the morphological status of these syllables is the primary cause of their characteristic acoustic patterns, and that their segmental composition dictates further reduction processes they may undergo due to weaker prosodic contexts, higher word frequency, casual register, and other influences