Is there a cheap Teleprompter software that supports foreign languages?
If you have a Mac, Presentation Prompter had a few good reviews I found when doing some research.  I don't have a Mac to try it, but it appears to have mirror modes and is listed as having RTF support.

It is also worth pointing out you may be able to setup the necessary mirroring on a particular output desktop rather than having the prompting software have to support it.  This could possibly make the software that didn't have the needed mirroring option work for you.

If that doesn't work, MirrorScript appears to have a free teleprompting software that works with PC and international characters.  They also offer an entire list of alternative prompting software that might be worth looking in to if they don't meet your needs for other reasons.