Time and Thyme Are not Homophones: The Effect of Lemma Frequency on Word Durations in Spontaneous Speech

Frequent words tend to shorten. But do homophone pairs, such as time and thyme, shorten equally if one member of the pair is frequent? This study reports an analysis of roughly 90,000 tokens of homophones in the Switchboard corpus of American English telephone conversations, in which it was found that high-frequency words like time are significantly shorter than their low-frequency homophones like thyme. The effect of lemma frequency persisted when local speaking rate, predictability from neighboring words, position relative to pauses, syntactic category, and orthographic regularity were brought under statistical control. These findings have theoretical implications for the locus of frequency information in linguistic competence and in models of language production, and for the role of articulatory routinization in shortening.