Did some testing and found that for the Portuguese language there is a very small number of rules available. I say this, compared with the grammar checker available for LibreOffice. There is a maintainer of the Portuguese language? I would like to help, although at first I had thought to be quite complex to create new rules.
I also noticed that in the case of spelling errors, using pt-BR or pt-PT, the LT reports that there is a possible spelling error, but does not suggest words for correction. Already in English, he reports the spell error and suggests words. Would be some error related to the Portuguese language?
A layman’s question: would there be any way to import existing rules in the grammar checker of LibreOffice (using lightproof) for LanguageTool?
welcome to LanguageTool! Portuguese (PT) is maintained by Marco A.G.Pinto (marcoagpinto (Marco A.G.Pinto) · GitHub), Portuguese (BR) doesn’t have a maintainer. Contributions are welcome for both, of course. Rules that are not too complicated can be developed with Criar uma nova regra LanguageTool
I mean port rules from LightProof to LanguageTool. There are addon to LibreOffice, that uses lightproof, that have a lot of portuguese rules ready, and works fine.
The way LightProof works is a bit different from the way LT works. I think it’s difficult to port rules automatically. You’d probably need to learn how LT works (see Development Overview - LanguageTool Wiki), and then start porting rule by rule.