As suggested in another question, I'm asking this here.
I tried the procedure pointed out in the referred question, but then when I try to log in to Battle.Net from the Diablo 3 game, I get the following error message:
The client does not match the account's native language. Please use the game's original client. (error 81)
I bought my copy of Diablo 3 in Brazil. I think that this is the problem: I can only download the Brazilian Portuguese game client from Battle.net website. Other languages are not available for me to download, even though I use my battle.net account in english.
Best Answer
Blizzard announced that the retail versions of Diablo III would be locked to the region language, so if you bought yours in Brazil, your key is a Latin key and you'll only be able to play it in Brazilian Portuguese or Spanish.
Blizzard said that they made it this way in order to prevent what you did, to buy a cheaper game in another region (Brazil, Russia for example) and play the game in your natural language.
You can only choose your language freely in the special edition retail and the digital versions.
Here's an article that explains this further.