Phonetic correlates of prefixedness in four varieties of English

Studies show that phonetic detail signals morphological structure. Previous studies of English prefixes examined one dialect and speech style, and/or measured only duration. This study examines phonetic detail of prefix and nonprefix mis- and dis- (e.g. discolour, discover) in four dialects of natural conversational English: New Zealand, USA (Ohio), UK (Glasgow and Liverpool). Principal component (PC) analyses reduced 14 acoustic variables to five dimensions of variation: [s] duration, [s] spectral shape, vowel duration, vowel quality and [s] ‘low-frequency cutoff’ frequency. We assessed whether these dimensions are affected by prefixedness, in a binary or gradient fashion, and by control predictors of word frequency, early/late lexical stress, the fourth phoneme, and mis-dis-. The dialects used different combinations of PCs to signal prefix status, with each PC used by at least one dialect. Vowel duration is the most statistically-robust and generalizable effect. Whether or not the fourth phoneme is a stop is also influential. All PCs showed binary effects of prefix status. Within prefixes, vowel quality and [s] low-frequency cutoff showed gradient effects, covarying with judged degree of prefixedness. The observed patterns reflect how each dialect adjusts these syllables’ prosodic weight to conform with its dialect-specific speech rhythm and patterns of syllable reduction.