Which of the following is a temporal acoustic measure?

Voice onset time (VOT) is a temporal acoustic measure because it specifically assesses the timing aspect of speech production. VOT refers to the interval between the release of a plosive consonant and the onset of vocal fold vibration for the following vowel. This measure is crucial for distinguishing between voiced and voiceless plosives in various languages, as it provides information on how quickly the laryngeal activity begins following the consonant's release.

In contrast, fundamental frequency, while related to the pitch of the voice, is more about the frequency properties of the voice rather than a timing metric. Syllable duration does indeed involve timing; however, it focuses on the length of whole syllable units rather than the specific timing of consonant release and vocal fold vibration. Formant frequencies are also frequency-based measures that characterize the resonant frequencies of the vocal tract and do not directly address temporal aspects of speech. Thus, VOT stands out as a specific measure of timing in the context of speech sounds.