From Win Wenger:

The main game is an extension of the one parents play with their babbling child anyway. The child says do-dah-BAAAH, the parent says do-dah-BAAH. The device repeats both within the same sequence. The child gets from that a cluster of benefits - - his own direct feedback, the clear demonstration that the tape is feeding back sounds, the comparison otherwise hard to obtain accurately between baby's speaking and parent's speaking.

Other games I remember include the parent making other kinds of sound, visibly knocking blocks together or ringing a bell or whatever, and the device duly repeating back those sounds so the infant SEES this process in action. This then, of course, also encourages the infant to make other kinds of sounds besides the vocal, but that shouldn't much get in the way of the vocal - at least it didn't in the instances I observed.

With a very short delay as Stuttering Therapy Software

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