I learned Czech in 1984 at the Defense Language Institute in Monterey, CA. (OH, do I have to go to a schoo in Monterey? Darn.
) I'm not fluent in it any longer, but I still remember quite a bit and I still have my Czech and my Slovak dictionaries.
The Army also tried to teach me Arabic. Well, I graduated but I can't claim to have learned Arabic. At my best, I was most comfortable speaking to little kids. I can read a little Arabic, but I <b>never</b> was good at it. It's a beautiful language though. If I had been younger, I might have done better with it, but it's tough learning a language of any kind at 29.
Oh, and as far as difficult languages go, Arabic, Chinese-Mandarin, Japanese and Korean are considered CAT IV (the hardest). Czech and Slovak were CAT III as are most of the Slavic languages. But at least Czech used a Roman alphabet. Cyrillic would have been much tougher.