The Center for Advanced Study in Theoretical Linguistics (CASTL) was created in June 2002 as a Center of Excellence (CoE) under the Norwegian Research Council's CoE scheme.

CASTL was founded by a core group of internationally respected linguists from the Department of Linguistics and the Department of English at the University of Tromsø, but includes researchers in other language departments and institutions in Tromsø, mainly operating out of the Faculty of Humanities.

The center's objective is to conduct comparative studies to explore the characteristic elements of linguistic variation, and to determine the parameters along which languages differ. The research is intended to provide a theoretical grounding for language planning, language teaching, language technology, and the standardization and establishment of orthographies.

The CoE status involves a substantial level of government funding for a ten-year period, allowing CASTL to continue and to expand its activities.

Upon the creation of the Center, Professor Noam Chomsky of MIT sent the following congratulatory message:

"That's really fabulous news. It would be hard to invent something better. Can't think of anything like it anywhere. But just think of the responsibility you all now have to the future of the field. "