Hi, bumping this thread. I have the same issue, I don´t understand how to write the prompt from your description above.
If I want to write a snippet of text in French how would the prompt look using your example above?
One thing that works sometimes for free-form output is simply taking a common French word (like some pronoun or “I” or whatever) and starting your answer with it. (Maybe you could also select one at random.) This way the generation is still pretty unconstrained, but very unlikely to be English.