Hey blackhornet, I'm not sure you're aware of that and I thought you might want to know.
There is a problem with Thai language. They have some kind of "half letters" and when GYFM filters the input to remove duplicates it changes Thai letters and the sprite font can't be used properly. I'm not sure how Thai letters work and if you'd be interested in investigating that (I belive it would take some time), but I think the quick workaround would be to give an option for automated filtering (duplicates removal) or manual. So we could just paste the letters we use and export them without filtering.
I think other Asian languages with "combined characters" might have the same issue.