Not a bad deal for $49. “MIDISpeak Module – Version 2, The Talking Toy MIDI RetrofitAdds a standard MIDI IN port to your Speak & Spell, Speak & Read, or Speak & Math. Non-English versions also supported. Trigger thousands of sounds–words, word fragments, garbled speech, percussion and bizarre sound effects.” Link. In MAKE 04 we also show you how to build music toys like this. Modify a Casio keyboard (or other electronic audio stuff) and start playing some of the strangest sounds you’ve ever heard.
MIDISpeak: Speak & Spell MIDI Kit