WiX v3.5 UI library supports 30+ languages.
There was a small change made to the WiX toolset recently that added dialogs to the WixUI library that are shown when patching. That part of the change was straight forward, the tricky part was that the dialog needed to support all the existing languages or the patch UI could come up in a different language (English) than the initial install. Fortunately, the Office Communications Server team (who was adding the patch dialog) was willing to localize the dialogs in all languages they support, 30+ of them. That’s good news but there is some bad news.
Original post by Rob Mensching