What is the primary type of sounds to which VOT applies?

The primary type of sounds to which Voice Onset Time (VOT) applies is stop consonants. VOT is a measure used to determine the timing of voicing in relation to the release of a stop consonant. It refers to the time lag between the release of the oral closure of a stop and the onset of vocal fold vibration.

In the context of speech sounds, stop consonants, such as /p/, /b/, /t/, and /d/, require precise timing to distinguish between voiced and voiceless versions of these sounds. For example, the difference in VOT can help to differentiate between /b/ (voiced) and /p/ (voiceless). In contrast, vowel sounds, fricative sounds, and nasal sounds do not utilize VOT in the same manner, as they do not involve the same kind of oral closure and subsequent release that is characteristic of stop consonants. This makes VOT a key feature in the phonetic analysis and classification of stop consonants specifically.