The harmonics vary greatly between different wovels. I'm sure you know that for example the "o" vowel singed at 200Hz will have a different spectrum than an "i" wovel singed at the same pitch.
Indeed but as I read it, the context of the statement was “listening”, a trick to help identify freqs when listening. With pitched sounds we tend not to directly hear the harmonics, we tend to hear the pitch of the fundamental and perceive the higher harmonics as timbral information rather than as pitches. A “oo” vowel at 200Hz will sound roughly the same pitch as say an “ee” sound, probably within 100Hz or so, you won’t perceive it as a 4kHz pitch. If you want to train your listening to identify pitches/ranges of pitches, then using musical notes or a sine wave generator is far more effective/accurate.
I don't know if he is right about which vowels accentuate which part of the spectrum though and it can depend on how exactly the vowel is pronounced anyways.
That’s an additional problem, different pronunciations/vocalisations (saying the vowel quietly or loudly for example) will change the spectrum of higher harmonics and different voices will also change it. Plus, some of the other sounds referenced, for example the “sss” sound, doesn’t have a defined fundamental and harmonics, it’s far more comparable to band limited noise which also varies considerably from person to person and according to how it’s vocalised.
63 Hz "abdomen"
125 Hz "chest"
250 Hz "oo"
500 Hz "o"
1000 Hz "ah"
2000 Hz "a"
4000 Hz "ee"
8000 Hz "s"
16000 Hz "ts"
It is not about the fundamental frequencies or overall bandwidth of the sounds, but the characteristic frequency ranges.
No, it’s not. As far as listening is concerned, it IS about the fundamental freqs, where a fundamental freq is clearly defined, such as with vowels. I’m not sure where you got that list from but it appears to be nonsense and not only due to the facts already mentioned! For example, the word “chest” obviously ends with the “s” and “t” sounds, the “s” sound is a band of noise (probably around 2-8kHz), the “t” sound is also a noise band but probably starting lower (around 1kHz) but extending to 12kHz or so and the “ch” is also a band, typically starting in the mid or high hundreds and extending to around 6kHz or so, so where does the 125Hz come from? ”Abdomen” is even worse because it is actually 3 different syllables, each with different freqs/harmonics AND none of them have any content at 63Hz! In spoken language there is virtually never any content below 80Hz (which is why mics sometimes have an optional 80Hz roll-off). There are some exceptionally low male voices but it’s still very rare for there to be content as low as 63Hz. With a typical adult male voice there probably would be anything below about 100Hz when pronouncing the word “abdomen”, with the potential exception of a “plosive” on the “b”. In fact, the first two items in your list are so absurd I wonder if you mean them to be different to the other items in the list, for example where you might physically sense those freqs (when using speakers at a high level) rather than vocal sounds which produce those freqs?
All the freqs I’ve given above are extremely vague, they vary significantly from person to person, also according to dialect and even vary very significantly from the same person. The same person may pronounce the letter “t” similarly to the action of spitting, which would produce content up to 16kHz or more, or on another occasion more like a “duh” type of sound which might not have much content above 5kHz or so. With all the vagaries and potential for such large variations, using vocal sounds as a reference for frequency/pitch training is arguably amongst the very worst content one could use IMHO, a sine wave generator or MIDI instrument would be far better, both of which can be obtained with free audio software or even more simply on websites, there are numerous online virtual pianos and sine wave generators available for example.
G