All ACSII character sets work in DicsoverText. We have done formal testing of search, filtering, display, coding, and machine-learning in Chinese and Arabic.
User have reported success in the European romance languages, such as French, Spanish, and Italian. In the past we have supported projects in Hebrew, Polish, and a range of other dialects.
If you have a novel language and want to see if it works, just sign up for a free trial and test it out. If it does not work, let us know and we will try to make the changes needed to support the new language.