Some accounts of acoustic reduction propose that variation in word duration is a reflection of the speaker's internal production processes, but it is unclear why lengthening within a word benefits planning. The present study examines whether variability in word length is partly attributable to phonological encoding. In an event-description task, speakers produced words with longer durations when the word shared part of its phonology with a previously articulated word than when it did not. More importantly, lengthening was greater when the overlap was word-initial than when it was word-final. These differences in duration are in line with predictions of serial phonological competition models, which claim that words that overlap in onsets create more competition than words that overlap in offsets and are thus more difficult to produce. That word duration is sensitive to differences in production difficulty suggests a link between speakers' duration choices and phonological encoding. We propose that lengthening provides the production system with the necessary processing time to produce a word's sounds.
Keywords: Acoustic reduction; Processing time; Word duration.