Has anyone else ever come across the idea, I don't even know if it's still current, but I remember learning a bit about them years ago. It would seem that there are age related windows of opportunity for the brain to learn certain things, like language, children who are not exposed to human languages struggle with them if they have to try and pick up speach later. They will however be fluent in the language of the animals that brought them up, a lot of this research was done on feral children who for no fault of thier own had been abandoned by thier parents/carers at a young age and were later adopted by animals usually dogs, I remember seeing a couple of children who had been found and had learned to speak human languages again, but were still fluent in the language of thier adopted species.