>>40527532An original concept, while the anime was in pre-production, was to have the wild Pokemon only say their name, because they're wild, but as a Pokemon became closer with a trainer, it would slowly develop human speech - First only their name, like a wild Pokemon, but would eventually lead to baby talk, then pre-school speech, and so on.
I don't know if the reason why they changed it was also talked about, publicly, but I think I recall it being about straying too far from the idea of monsters fighting, and the implications of training sapient creatures to fight for the amusement of trainers; which is why a concept for the anime would also have the Pokemon revolt at the end of the series, as they thought it would only last a single season at the time. But, it's clear to see why GameFreak and/or Nintendo didn't approve of that.
Meowth was a left over of the idea, which is why he talked in the first place.
