> Having used various things that claim to be natural language, I find that to use them effectively, I end up needing to learn their particular structured language.

This makes sense. Are there any specific examples of products that you have used that you had to do this?

> ...selecting lists with plural nouns and individual records with singular nouns...

Yes, this is for sure a failure case. I believe I have some means to work around this, fwiw.

> if I'm going to learn a structured language anyway, I would usually prefer to learn the underlying language, and not an imperfect abstraction.

I feel like I get what you are saying here, but some more concrete examples would help. Is there a "structured language" you are referring to?