I did a study back in 1991 for a certain government agency on what languages were still in use in this old world. There were literally thousands. I originally tried to draw the line at languages with at least 10,000 speakers (about 1,700 meet that criteria), but some very minor ones were deemed of strategic importance and I just got sucked in further and further as the data accumulated.
I imagine. With the WoT a number of arcane languages have become more important. Chechen, for instance (it's related to Basque, IIRC, so it's got to be pretty hard to learn) but there are Chechens attacking our soldiers in Iraq and Afghanistan, and training European Muslims in chemical warfare and "martyrdom operations", so it might be worth learning.