This paper presents a large-scale study of silent pause duration, based on the analysis of ca. 6000 pauses in 5 hours of read and spontaneous speech in five languages. The distribution of pauses appears as trimodal, suggesting a categorization in brief (< 200 ms), medium (200-1000 ms) and long (> 1000 ms) pauses, the latter occurring only in spontaneous speech. The study reveals possible methodological flaws in previous research in which statistical tests that rely on normality assumption (such as the ANOVA) are routinely applied on non-transformed data, although distributions are far from normal. It also emphasizes the dangerous effect of thresholds, which are very commonly applied in the literature for practical reasons, but can lead to totally false conclusions when comparing speech styles, languages or speakers.