>I am surprised that Greek should be so much more difficult for Americans than e.g. Danish.

I think Greek is ranked with Russian because for both languages you require a different alphabet which means that it takes a long time to get off first base.

I learnt Russian at the same time as a friend learnt (ancient) Greek and I'd say that our learning paths were similar - a very slow start, getting faster once you realised that many words were not that difficult when you could actually read them - radio(paguo), music, piano etc. Anyone who has ever studied maths/math has a head start with the Greek alphabet, it just takes time to build up speed.