Do they understand Fyromian................?

A little bit. Since they live in FYR of Macedonia, they can probably understand their language. Also, about the problem with Mika, their country's name is FYROM which stands for former Yugoslav Republic of Macedonia. It's no bad to call them like that, it's their official name, although it's not what they want. The people and the language are officially called Slavomacedonian but they should've been called FYROMian. You're right Rasman.