[danhau]

Oh and I forgot: I can play some instruments, but the voice is the cruelest one to learn. You can‘t „see“ what you are actually doing (wrong). And most of the time you can‘t even feel it very well. This why vocal training is full of analogies and imagery.

[stavros]

I wish it weren't. I would have gotten a lot more mileage out of "force a yawn, see what your mouth does, and do that" rather than "more space, more space, open up!".

[austinjp]

Have a look at Complete Vocal Technique.

https://completevocalinstitute.com/complete-vocal-technique/

Their work includes pedagogical research to develop a consistent terminology which abandons lots of outdated and confusing terms such as you mention. No more ambiguous words like "project" or "space" or "support".

Their research also includes using endosciopic cameras to directly observe the vocal tracts of professional singers.

I've not actually trained with them, I just like their research and approach.