In addition to Western languages, DITA2Go supports Russian, Greek, and Central/Eastern European languages. For HTML/XML outputs DITA2Go supports all languages, via Unicode (UTF-8). For RTF outputs, DITA2Go supports only single-byte languages, although it is possible to produce decent Japanese RTF for Word.
DITA2Go does not currently support non-Unicode double-byte languages, nor right-to-left languages such as Hebrew and Arabic. However, if you use DITA2Go to produce Microsoft HTML Help, you can specify Japanese, Chinese, or Korean output, via Asian code pages that you must download separately; see §1.2 What you need to have.