Usually you should be able to wire the speaker terminals from a toy to a mono jack socket to create a line out. + to tip and - to sleeve although it doesn't matter to much which way round they are. If the out output is to high use this circuit to calm it down a bit
a higher value of R1 will give a lower output. Theres all kinds of problems you can come accross with outputs but a lot of them have been covered on this forum so do a search.