The Philips 'Language Director' series on CD-i were directly ported from the cassette tape version, also produced by Philips

Philips released a full set of CD-i discs in the Language Director series in 1992. The discs were produced by Philips IMS in Zurich. We know that the following languages were produced: English, German, French and Spanish. Each language has three levels and each level contains of three discs that were presented in a box like these. They were marketed at a professional audience, not readily to consumers. They were all base case titles, no Digital Video Cartridge was required. According to the brochure, each language offered six levels, but I have never seen more than three levels per language.

When you dive a bit deeper in the history of language courses made by Philips, more details are uncovered. Before Philips developed the CD-i (Around 1977 and the years after that) Philips was also active with developing language course, but at that time on cassette tapes. Philips even developed a special cassette recorder. It was special because these cassette recorders could play and record at the same time! In a cassette tape, the tape is divided in four tracks, 2x stereo tracks for both sides. But with this special recorder, the other two tracks were used for recording. So you could hear yourself back when you were practicing the exercises on the tape. If you would play this special tape in a regular cassette player, you would hear your recordings backwards.