So varied that it is difficult to give only one answer. Intelligence drives all operations in the military, and SIGINT is absolutely vital to the conduct of modern warfare. Language skills are in demand at a variety of different levels of the Army intelligence enterprise. Cryptologic linguists might spend their day (or night) supporting special operations units in close contact with the enemy, or behind a computer collecting and processing intelligence information.
There is no one answer to this question, and as an initial enlistee, you do not get to choose much about your outcome. You might travel in the Army, but it's not a vacation.