Defense Language Continuing Education Act of 2021 This bill requires the Office of the Under Secretary of Defense for Personnel and Readiness within the Department of Defense (DOD) to establish policies and procedures to provide continuing language education to linguists of the Army, Navy, Air Force, Marine Corps, or Space Force who have made the transition from formal training programs to operational and staff assignments. The office must establish a procedure by which the military branches may reimburse a DOD organization that provides continuing language education. The office must brief Congress on the implementation of the policies and procedures established by this bill.