Multi site language

Hi. Managing translations during upgrade has proven to be bit of an issue, since language file structure has changed and translations now seems stored in DB – however we’ve managed to handle it. However, we’ve noticed that since all translations are handled within the theme, the language_attributes() function always returns en_US no matter which site/language is displayed. How do we fix this? Wouldn’t it perhaps be better for us to handle all translations via e.g. the WPML plugin? Ideas, comments and solutions are very, very welcome 🙂