Voiceless unaspirated plosives

For voiceless unaspirated plosives, there is no voicing during the closure. Vocal fold vibration starts very soon (about 5–20 ms) after the release of the closure.

Unaspirated plosives are regularly found in English in the syllable initial clusters [sp st sk]. If you say ‘a pie’ and ‘a spy’ with your hand just in front of your mouth, you will feel a noticeable difference: for ‘a pie’, you will feel a stronger puff of air than for ‘a spy’. This corresponds to the difference in aspiration, and a shorter VOT for these plosives. If you can produce ‘a spy’, but remove the [s] and keep an unaspirated plosive, the resulting sound will probably be closer to the English sound [b] than the [p] sound. This is because when preceded by a voiceless sound or when utterance initial, the closure for [b d g] is usually voiceless. On release into a following vowel, voicing starts almost immediately.