> perhaps only in English

Wouldn't it work better to just write the thing in whatever language they can actually write in and then do a straightforward translation in a single pass?

> someone who is a lousy writer with deep domain knowledge going back and forth with the LLM to express some insight or communicate some information that the LLM would not produce on its own

This sounds reasonable on its face, but how often does it actually come up that somebody can't clearly express an idea in writing on their own but can somehow get an LLM to clearly express it by writing a series of prompts to the LLM?

And, if it does come up, why don't they just have that conversation with me, instead?

> Wouldn't it work better to just write the thing in whatever language they can actually write in and then do a straightforward translation in a single pass?

Nontrivial translation tools are AI(neural net)-based tools (although not necessary LLM). Whole transformer neural net architecture was originally designed for translation.