Mark Kinsler reminds us of some "nylon cable tie" devices that talked
when you ran your fingernail down them.  We had them in the UK too.

Back in about 1980 a work colleague appeared with one that had an
advertising slogan on it.  The product was "Fruity Friends Yoghurt"
and the strip said "Hello Fruity Friends!".

I think they recommended cutting a small slot in one of their plastic
pots and pulling the strip through that.  The pot acted as a resonator.
We all used to play with it in the lab and it eventually wore out
completely.

I never did try the product!

Jeffrey Borinsky