I dunno. This one seems trickier to me. Since it’s not really the code that’s the key part of the AI—it’s the trained numerical weights. Can you read and write in this language of floating point numbers? I doubt that. So perhaps yes you can write the code that could train a LLM and you could freely distribute that, but does freedom of speech allow you to train the model weights and distribute those?
Writing code absolutely does not fall under free speech. Neither does any product development. Ford isn't allowed to ignore seat belt requirements and claim the government is infringing on the designers' freedom of speech/expression.
That case was extremely specific and doesn't mean that all code written falls under free speech.
It was also tried in a very different time. Given that we can't even allow free speech on digital platforms today, I'm not sure that many courts would allow for free speech claims to fall under the first amendment.
There is freedom of speech regardless if it's written in English or C.