A Xenolinguist is a person who specialized in the studying and speaking of alien languages such as the Na'vi Language. Xenolinguists are extremely important on Pandora, as they are able to communicate with the planet's sentient natives, the Na'vi.
The RDA employs several xenolinguists on Pandora. When humanity first arrived on the moon, it was necessary to establish diplomatic relations with the Na'vi. Most of the xenolinguists on Pandora are not military, but scientists involved with the Avatar Program. The known xenolinguists are Dr. Augustine and Norm Spellman.