First post of the year, I hope this finds you well (or at least better than I've been with a fever and head cold.)
The Bell & Howell Language Master was a language teaching system used by language and speech therapy instructors in the 1960s and '70s. It used 3 1/2" x 9" inch cards with a strip of magnetic tape that ran near the bottom of the card with two tracks that ran for 3 seconds. One for the instructor, the other for the student. It allowed switching between tracks to compare instructor/student pronunciation.
*Guitar effects pedal (as shown in the video) not included.