"A most beautiful toy that demonstrates synthetic speech is the Speaking Picture Book, made in Germany in 1895. The mechanism, which produces nine different animal sounds, consists of seven bellows with complicated flute pipes with stops reminiscent of the Kratzenstein pipes. When the cover is opened, one reads a verse about a cow, sees a picture of it, and follows an arrow pointing to a string. When the string is pulled, a realistic moo sounds out...
"...this Victorian toy, primitive though it is, is probably still the best synthetic speech toy to reach the market, and was certainly the predecessor of the Vocoder and of modern electronic voice synthesizers."
There is also some discussion of toy animals that emit accurate sounds when the toy is turned or squeezed -- crude examples can still be found today, but the variety and accuracy of older specimens probably represent a lost art.
My favorite toy of this kind is a 1940s piggy bank designed for war-bond savings, bright yellow and painted with Hitler's face. Whenever a coin was deposited, der Fuhrer squealed.