Here's "how to" control those toy motor props that proliferate on
store shelves around Halloween.  So often they are neat-O but
don't speak the words we would like them to say.

For very little cost and work you can build this circuit and replace
the one that comes with the toy.  Then all you do is feed this board
with sound from any sound source and it "speaks your language" !

I believe all five(5) circuit board components, six(6) if you count the circuit board, itself,  for soldering components onto,  are available from Radio-Shack (R-S).  The power supply could be the battery box that comes with the prop or a
wall transformer.   R-S carries these also - be sure voltage matches that of the toy (battery supply).

Note in diagram above the two transistors have terminals labelled "e = emitter", "b" = base, "c" = collector.
Relate these to lead diagram on the R-S package and there should be no problem in wiring them correctly.

Once this circuit is built, connect to positive power leads of the motor/s and power supply as shown above.
Often the polarity of a toy motor doesn't matter,  test this first by momentarily connecting the two leads
of the motor, to the power supply directly,  then reverse leads (plus/minus) if there's a difference
in action - polarity matters, but usually it doesn't.

The RED and WHITE leads from the audio transformer are connected to the two terminals of the speaker, leaving the
existing wires that power the speaker connected also.
 

 Short Video Clip of (Store Bought) Prop Activated by this Circuit