Lingua...something

This summer I'll have the great honor of clerking for a judge. As such, I'll actually have quite a bit of free time (summer dockets are rarely that dense).

One of the things I'd like to do is learn a language in my spare time. I'd like to find a good audio series, but something beyond the normal tourist courses. In other words, I want to be able to say more than just "where is the lavatory?" by September.

I'm thinking of learning either Latin, Japanese, Italian, or German. I've seen some audio courses supposedly drawn up by the Foreign Service, for instance, which purport to efficiently allow one to achieve competency in a given language.

Does anyone have any advice or suggests on a certain brand of courses I should invest in? Thanks in advance.