The Linguistics department was approved and formalized in 1973: “John Oller Jr., an enthusiastic and aggressive young applied linguist at UCLA, was hired (with an appointment in Educational Foundations) to serve as director of the [Linguistics] Program. He quickly marshalled forces, prepared a new proposal, and secured approval for a Department of Linguistics in the College of Arts and Sciences effective July 1, 1973.” (Bills MS, 1989)
But the department continued under an interdisciplinary system until 1988.