VOT，英文全称为voice onset time，中文有「嗓音起始时间」「浊音起始时间」「发声起始时间」「声带震动起始时间」等各色缤纷的译法，大抵翻译仅襄阐释不做正名，称呼提举处多直引字母缩略形VOT。VOT的具体含义也不完全与字面吻合，其实际所指为：某一辅音从除阻的一刻到声带开始震动，中间所经过的时间。

三种主要的塞音发声类型可以从VOT角度进行分析：

由于送气和有声（声带震动）都不是绝对的概念，允许有不同程度的中间值存在，所以我们常常会用相对的术语「强」（fortis）和「弱」（lenis）来描述呈二元对立的两个辅音系列。将VOT高的界定为「强辅音」，将VOT低的界定为「弱辅音」。当然，强弱都是相对而言的，不同的语言里强弱的涵盖可以迥乎不同。

In phonetics, voice-onset time (VOT) is a feature of the production of stop consonants. It is defined as the length of time that passes between the release of a stop consonant and the onset of voicing, the vibration of the vocal folds, or, according to other authors, periodicity. Some authors allow negative values to mark voicing that begins during the period of articulatory closure for the consonant and continues in the release, for those unaspirated voiced stops in which there is no voicing present at the instant of articulatory closure.