Chess is defined by a small number of pieces, and rules for their movement around the board. But there are an infinite number of ways for an individual chess game to play out.
Language is like that. A language is a potentially infinite set of possible utterances. But any speaker of a language can instantly tell a whether a sentence 'follows the rules' or not, even if they have never heard it before--even if they don't know all the words!
Linguistics is the scientific study of language--the search for the units, rules, and internal logic of a language, and of all human languages.
Moshe Nahir has in the past worked on the revitalization of Hebrew.
H. C. Wolfart has examined legal issues surrounding the language of Cree and the courts (e.g., "Terms of Treaty: The Language Barrier and the Courts", a plenary lecture, Canadian Linguistic Association/Canadian Association for Applied Linguistics, 2004).
Terry Janzen, Erin Wilkinson and Kevin Russell are currently expanding our focus on American Sign Language (ASL), the primary language of Deaf communities in North America. While to date their work has been descriptive, it is certainly the case that Deaf people have encountered much discrimination and language suppression, that is, there have often been efforts to suppress the use of signed language, especially by deaf children in educational settings. The Deaf community in Winnipeg has voiced their desire to see this be acknowledged and documented, especially in conjunction with the arrival of the Human Rights Museum. Thus, Janzen, Wilkinson and Russell have begun to discuss what the role of the Department of Linguistics might be in these endeavours.