Forms of English Function Words — Effects of Disfluencies , Turn Position , Age and Sex , and Predictability
This study examines the role of several non–phonetic factors in the reduction of ten frequent English function words ( I, and, the, that, a, you, to, of, it , and in) in the phoneticallytranscribed portion of the Switchboard corpus of spontaneous telephone conversations. Using ordinary linear and logistic regression models, we examined the length of the words and whether their vowels were full or reduced. We show that function words are more likely to be longer or unreduced when they are turn–initial or utterance–final, when the speaker is female (mostly but not completely due to slower rate of speech) and when the word is surprising given the previous or following words. Finally, focusing on finer details of the effect of planning problems on reduction, we show that filled pauses ( uh and um) are the strongest factor in predicting lengthening of a previous function word. The results bear on issues in speech recognition and models of speech production.