The Speak & Spell line is a series of electronic handheld educational toys created by Texas Instruments that consist of a speech synthesizer, a keyboard, and a receptor slot to receive one of a collection of ROM game  library modules (collectively covered under patent US 3934233). The first Speak & Spell was introduced at the summer Consumer Electronics Show in June 1978,  making it one of the earliest handheld electronic devices with a visual display to use interchangeable game cartridges.

Info gleaned from Wikipedia