I am keeping up with written Vietnamese pretty well because I write back and forth to a couple of nuns in Cam Duc. I also trade email with several other folks almost daily. That started out as quite a challenge because over there they only have INET access at INET cafes where none of the machines have Vietnamese fonts. So they write to me in Vietnamese with no marks. Each word can have a couple dozen different translations. I am getting the hang of it now and don't have to use my dictionaries so much. I write back in a proper font. One 15 y.o. girl that I email with is a fanatic about learning English so she can get rich when the VC lid shatters in a couple of years. She writes to me in English and I write back in Vietnamese.
It's my understanding that Vietnamese, though a Sino-Tibetan language, is written in the Roman alphabet (though even some languages using the Roman alphabet require specialized fonts, ie, Turkish etc.).