Time is essential to speech. The duration of speech segments plays a critical role in the perceptual identification of these segments, and therefore in that of spoken words. Here, using a French word identification task, we show that vowels are perceived as shorter when attention is divided between two tasks, as compared to a single task control condition. This temporal underestimation pattern is consistent with attentional models of timing and hence demonstrates that vowel duration is explicitly estimated using a central general-purpose timer. (Contains 1 table and 2 figures.)