Install SharePoint Language Packs in Windows 7

If you are developing directly in your machine, in a Windows 7 environment, and try installing a Language Pack, it will fail because of the default requirements (Windows Server 2008).

To make it work, you need to extract the package and the change a configuration file.

1. Execute "ServerLanguagePack.exe /extract:<your_dir>"
2. Open <your_dir>\Files\Setup\config.xml and add the directive "<Setting Id="AllowWindowsClientInstall" Value="True"/>"

That's it!
There is a post about this in MSDN, here.