Exolinguistics, also known as xenolinguistics, is a branch of linguistics centering on the study of alien languages, including their phonetics, phonology, morphology and syntax. 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")
In an alternate reality, Nyota Uhura's focus of study as a cadet at Starfleet Academy was in xenolinguistics. James T. Kirk impressed Uhura when he demonstrated knowledge of the study, as she had originally thought that he was merely "a dumb hick who only had sex with farm animals." (Star Trek)