The Intellivoice Voice Synthesis Module was an adapter for the Intellivision, Mattel's home video game console, that utilized a voice synthesizer to generate audible speech. The Intellivoice was a large, brown cartridge that plugged into the Intellivision's side-mounted cartridge slot; games specifically designed for the device could then be inserted into a slot provided on the right-hand side of the module.An International version of the Intellivoice was planned, but never released.