Overview’s natural language processing supports English and also Spanish, French, German, Italian, Dutch, Swedish, Norwegian, Arabic and Russian.
You can select your language as part of the document set import options, like this:
(You can also select the language when importing CSV files.)
This sets the language for Overview’s OCR, and also the list of “stop words” that Overview uses during its text processing, that is, words like “the” in English that don’t tell you anything about the contents of the document. It’s fairly easy to add new languages — contact us if you’ve got a set of documents in some language not supported here, and we can probably get a new language up and running in a day or two.
Note that this is the actual document processing, and the user interface will still be in English. But the application itself could appear in other languages too, if someone wants to translate the string file.
See also: How to process documents that contain more than one language.