Exolinguistics

From Memory Alpha, the free Star Trek reference.

Exolinguistics is a branch of linguistics centering on alien languages. One who studies exolinguistics is known as an exolinguist.

Hoshi Sato was an exolinguist who graduated second in her class and would later be Jonathan Archer's first choice for the mission aboard the Enterprise in 2151. She reasoned the importance of her role by stating that, "every inhabited world we come to is going to be filled with language. Some will have hundreds of them. He needs me here." (ENT: "Fight or Flight")

Before studying musical composition, Sek took exolinguistics. He found the science to be excessively theoretical. (VOY: "Repression")