Posted by Rick Denney on May 16, 2003 at 21:01:00:
In Reply to: "T" and "D" syllables posted by Adam Crowe on May 16, 2003 at 19:14:59:
With the T sound, you allow pressure to build behind the tongue before releasing it. That gives the T sound its percussive aspiration. With a D sound, you release the tongue before nearly as much pressure builds, which removes much of that percussive explosion of pressure. This is clearly audible when you play the tuba.
The timing of the vocalization is a separate process, but it's related. You can only vocalize when you have air moving across the vocal chords. If you pronounce a D while trying to build as much pressure as with a T, the vocal chord vibration will die because the tongue will prevent air movement once your mouth is pressurized. So, it's much easier to allow the D to speak before that pressure builds to that point.
In actual speech, the T is softer that our hard-tongued attack on the tuba. Thinking of D rather than T softens that attack and lets the tongue slightly shape the leading edge of the airflow rather than allow that pressure to stack up behind the tongue. If we actually vocalized our tonguing, we might find that what we think is a D when we tongue it on the tuba is more like a T when spoken, and our perception of a T might be more like a super-emphasized T sound that we'd never actually use in normal speech.
Rick "wiping spit off his monitor" Denney