Skins contain language strings, so for similar languages where the layout and fonts would be the same (e.g. European languages), you can typically use the same skin for multiple languages.

If you need to have specific localization such as logos, or for languages such as Chinese which have their own unique fonts, or even Arabic and Hebrew which may have special CSS markup to handle RtL (right-to-left) text, you can do this from the languages section too. See @12.1. Setting a skin for more information.