To my knowledge, all major LLMs are multilingual. This article could really have used an evaluation of existing models' European Portuguese capabilities.

E.g. gemma3:4b can fake simple conversations in several european languages, including portuguese, swedish and finnish.

It's just a database. If you push text in one language into it, it'll likely crap out stuff in that same language, unless the system prompt that also goes in with your query causes it not to.

The whole point of this project is to have an LLM that speaks European Portuguese, not Brazilian Portuguese.

The authors are pretty clearly trying to draw only from European Portuguese sources - I feel like there's a fairly widespread attitude here that the language is being overwhelmed by the sheer number of Brazilian speakers (which there is obviously at least some truth to).

I don't necessarily personally feel like preserving European Portuguese in amber is a worthwhile goal (anymore than it is productive for Brits to be prickly about the meteoric rise of US English)

Mutually intelligible, yes, but far from perfectly so. I speak both, as a native anglophone, and the difference is not so much “US vs British English” so much as “Guyanese English vs British English”. Like, fundamental points of grammar differ, the spoken rhythm and syllabic stress differs (poetry does not translate well between them), never mind just vocabulary. Continental Portuguese people tend to find it easier to understand brasileiros than vice versa, largely due to mostly one-way cultural exports, but to try to roll both into a single model would create a creole at best.