The department policy is that courses taken for credit toward either major (Linguistics or Cognitive Science) must be taken for a letter grade. Courses taken on a Pass/No Credit (P/NC) grading scheme do not count toward the major. In special cases the department may consider an exception to this policy: to make such a request please submit a petition to the department.
Regarding policy previous to 2020: the Cognitive Science major has had a consistent policy of not counting P/NC courses toward the major. The Linguistics major had no explicit policy in this regard prior to 2020; if you are a Linguistics major with a P/NC course taken prior to 2020, this will be exceptionally allowed to count toward your Linguistics major.