>jthree languages in 1 editbox -- maybe if you know what the languages will be, but if it is completely random, yep, not going to be easy. I do not know how it could be done.

Perhaps in an ActiveX control, just as...

>However can do that in web app.

...this could do it, but then you wouldn't be able to do anything much with string manipulation - spellcheck, search & replace etc, you'd have to write those from scratch, couldn't use fox's native dialogs. Cumbersome and tricky.