Stops produced with zero voice onset time have voicing that begins simultaneously (or nearly simultaneously) with the release of oral closure. The duration of voicing prior to the release of oral closure is 158 ms, which we report as a negative voice onset time of -158 ms. Voicing is evident in both the waveform, where periodic oscillations are present, as well as in the spectrogram where we can see a voice bar and vertical striations indicative of glottal pulses. Here we can see that voicing continues throughout the stop closure, which is shaded in gray. This spectrogram shows an example of a voiced bilabial stop, produced between two vowels. Stops that are produced with prevoicing, or negative VOT, will show evidence of voicing during the oral closure, followed by a release burst. As a result of this style of measurement, there are three types of VOT: pre-voicing, or voicing leadzero voicing, or short voicing lagand post-voicing, or long voicing lag First let’s consider the case of prevoiced stops. Note that VOT (like most durations in speech) is typically reported in milliseconds. Voicing before the burst is measured in negative numbers, while voicing that begins after the burst is measured in positive numbers. This is analogous to a number line, where the burst is located at zero. Phoneticians describe voice onset time (VOT) in plosives relative to the release burst. In stops, however, the timing of voicing relative to stop closure and release is variable. While voicing *could* begin and end at any time during sonorants or fricatives, it tends to persist throughout those sounds. Try this: how long can you sustain voicing in a voiced bilabial stop ? (what happens when you try to keep voicing going longer?) (Sidenote: since voiceless stops don’t involve voicing, you should be able to hold that closure as long as you can hold your breath) So, we can now see that there are physical limitations to how long voicing can overlap with oral stop closures. Since stops involve complete closure of the vocal tract, there is a limit to how much air can flow in order to create voicing. We won’t get into those here.) Try this: how long can you sustain a sound? – quite a long time! When we consider stops, things start to get a bit more interesting. In fricatives, this doesn’t really get in the way of voicing too much (although there are aerodynamic tradeoffs in order for both voicing and frication to happen at the same time. This will have implications for how and when voicing can occur. Try this: hum a bilabial nasal how long can keep it going?- Forever! In obstruents, on the other hand, there is constriction in the vocal tract, which impedes or obstructs airflow. Sonorants are typically voiced continuously throughout the entire duration because the vocal tract is open, allowing air to flow freely. First, recall that some sounds are typically voiced:- Sonorants While others come in pairs of either voiced or voiceless sounds- Obstruents Voicing depends on air being able to flow through the larynx in order to set the vocal folds in motion. Voice Onset Time is typically used only for stops/plosives, so let’s briefly take a moment to consider why this is. Why is a voiced sound produced without voicing? As it turns out, the alignment of voicing with oral closure during stops varies across languages, and we describe this alignment by referring to Voice Onset Time. If we remember that in the IPA the symbol stands for a voiced bilabial stop, this becomes very curious indeed. (The opposite pattern appears at the end of the phrase, where the vowel is followed by a voiceless stop.) If you look closely, you might also notice that there is a very brief interval of time where voicing stops during the closure of the sound. At other times, voicing alternates from one phone to the next, as we see at the start of this phrase where a voiceless stop is followed by voicing in a vowel. Without even listening to the audio, we can see that voicing is present by observing the voice bar here at the bottom of the spectrogram, and also by observing the periodic structure of the waveform. Sometimes, voicing persists throughout a number of phones, across both consonants and vowels, as we see here. When we examine the waveform and spectrogram, we can see that voicing starts and ends at various places throughout the phrase. Consider for a moment a phrase like “come and get it”. We use the terms “voiced” and “voiceless” to indicate whether the vocal folds are vibrating, but these terms do not tell us much about when those vibrations occur, relative to other events. In previous videos we have seen how voicing appears in waveform, spectrum and spectrogram, and we know that it is independent of place and manner in consonant production. This video just has a plain transcript, not time-aligned to the video Voicing is the result of vocal fold vibration.