I made a translation by creating an es_ar.json file with its respective translation inside, but it is still in English

I don't have much experience in this, with other mods I did them the same way and it works

You can see the other language jsons in my mod here: lang
Minecraft will reject json files that are malformed, check the json for errors here:
jsonformatter
or just google json checker.

Oh how stupid, I was missing a "
Added to favorites, it is very useful, thank you very much!

es_ar.zip
es_es.zip
(es_es may have some errors in exact words that I do not know)

Thanks for the contribution!