We(me and my group) usually play in portuguese using english terms, most words doesnt look good in portuguese, we use the original core rulebooks in english too, some newer members in our group sometimes uses a portuguese translated word and are instantly repressed for that hahahahaah, like you said, it usually sounds like something from a childs story... Some words are kinda close though and we use them in our native language like "elf" and "elfo"(or elfa, the a female elf).
By the way, im from Brasil(Brazil in english).