Upon login, players running Diablo 3 on a language different from their region are being prompted with Errors 81, 82 or 84. All of them read as follows:
"The client does not match the accounts native language. Please, use the game native client."
So far, this problem has been encountered in Chile, Brazil, Mexico, Denmark, Poland, Italy, Belgium, Russia, Hong Kong, and Korea, and there has been no official statement from Blizzard on the issue. Possibly, this is going to happen in every other country as well.
Update: there have been several responses from Blizzard. They can be found on this thread. To make a long story short, Blizzard representatives said everything is working exactly the way they want, thus implying that language restrictions will now be permanent. If you are not satisfied with Blizzard's response, please continue posting on this thread so that we can show how upset the fan base is and hope something will change in the upcoming days.
If you are experiencing the same problem, you are well-advised to submit a complain/ticket in the link below:
Sending as many complaints as possible is of paramount importance to make sure Blizzard will provide us with a solution for this problem. Otherwise, we will end up in the same position as Starcraft 2: everyone having to play the game in their "native languages" and in regionally-based servers.
Thank you in advance for your attention,