This is a corpus study on closure duration and VOT in English voiceless stops in word-initial position. 19 speakers' (10 female, 9 male) data from the Buckeye Speech corpus are used in the study. The first half of the paper introduces a novel approach of automatically finding the point of stop release in large speech database, using Mel spectral templates and similarity scores. The performance and robustness of the algorithm is discussed in detail. To our knowledge, this is also the first

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... tic measure of closure duration and VOT that is reported in detail in the literature. The second half of the paper studies the closure duration and VOT as calculated by the procedure described in the first half, and investigate the correlation between these durations and a number of linguistic and extra-linguistic factors. 1 Introduction Voice onset time (VOT) is a well-studied topic in phonetics. It has been shown that VOT in voiceless stops varies with a number of factors, among which the most established one is place of articulation. Zue (1976), Crystal and House (1987), and Byrd (1993) all find longer VOT for velars compared to labials and alveolars in connected read speech. Additionally, Crystal and House (1987) and Byrd (1993) both find that alveolars have on average longer releases than bilabials. In other words, the release duration increases as the point of contact moves from the lips to the velum. Cho and Ladefoged's (1999) cross-linguistic study of 18 languages suggests that this rule might be universally true. In recent years, more and more studies have focused on the relation between VOT and other possible correlates. Roughly speaking, the proposed correlates can be divided into two categories, speaker-related and non-speaker-related. The most widely-studied speaker-related factors are gender, age, speaking rate, lung volume, and individual talking style. In addition to place of production, other non-speaker-related factors include phonetic context, word frequency, and laboratory environmental setting.