I wonder if existing LLMs already know these patterns?

The Icelandic government has been proactive about helping OpenAI train its models on the language to stave off extinction: https://openai.com/index/government-of-iceland/

	▲	xigoi 4 days ago \| parent [-]
		If they’d rather support open-source models so the future of the language is not in the hands of a single foreign corporation…

Yes, this is an example of a problem that an LLM is ideally suited to solve.