Comment by ModernMech

If they go far enough with it they will be forced to understand it deeply. The LLM provides more leverage at the beginning because this project is a final exam for a first semester undergrad PL course, therefore there are a billion examples of “vaguely Java/Python/C imperative language with objects and functions” to train the LLM on.

Ultimately though, the LLM is going to become less useful as the language grows past its capabilities. If the language author doesn’t have a sufficient map of the language and a solid plan at that point, it will be the blind leading the blind. Which is how most lang dev goes so it should all work out.