When I joined up it was with a "guaranteed" contract as an 0311... basic infantry. It's what I wanted. I'd seen one too many John Wayne movies. During the first 72 hours of boot camp we had to take a huge battery of tests and one of them was an imaginary language test. My scores were high enough to get me called in for a "request" to change my contracted MOS to 2674. When signing up for duty stations after school you had your choice of 3... and then got the one that suited the "Good of the Corps". As I said before, it'll depend on your unit and how much down time you have. Given the high tempo of operations at the moment for the US military you'd have to find time as it came and not look to having a regular class schedule or a standing group of students.I think all the military is the same whatever country lol! I had a soldier come in the other day who wants to train with us, the recruiting office had told him he'd get time off to train ( he's BB TKD and Shotokan) but of course his unit just laughed when he asked. i've heard lot os similiar stories of people who wanted to be engineers, mechanics etc and being told to join the infantry first as 'they can always transfer', yeah right!
Reading orders and suchlike here they are asking for volunteers for people to learn Farsi and Arabic languages. Seems you have to be already in service before they'll take you on and teach you ..
On a side note a friend of mine became a signing for the deaf translator, it took a lot of time and a university degree but she gets paid now about £75 an hour to tanslate in courts, hospitals, tv studios etc. As well as being well paid she says it's a very enjoyable job,you get paid to make peoples lifes easier!