语音活性检测 (Voice activity detection，VAD), 也称为 speech activity detection or speech detection, 是一项用于语音处理的技术，目的是检测语音信号是否存在。 VAD技术主要用于语音编码和语音识别。它可以简化语音处理，也可用于在音频会话期间去除非语音片段：可以在IP电话应用中避免对静音数据包的编码和传输，节省计算时间和带宽。

VAD技术使得一些列基于语音的应用进程成为现实。因此，有一系列的VAD算法，具有不同的特性和延迟时间、灵敏度、精度和计算成本。有些VAD算法也提供了进一步的分析，例如讲话是否浊音、清音或持续。语音活动检测通常是与语言无关的。

Voice activity detection (VAD), also known as speech activity detection or speech detection, is a technique used in speech processing in which the presence or absence of human speech is detected. The main uses of VAD are in speech coding and speech recognition. It can facilitate speech processing, and can also be used to deactivate some processes during non-speech section of an audio session: it can avoid unnecessary coding/transmission of silence packets in Voice over Internet Protocol applications, saving on computation and on network bandwidth.