In my world there is an engineered species of changeling-like shapeshifters. Their lifecycle is similar to that of cuckoos (and the fair folk) of replacing human children with their own, who then run away into the wilderness once they reach maturity.
The original changelings would have spoken the language of their creators. However, would we expect subsequent generations of changelings to switch over to the language of their victims as their childhood will have been spent among people?
Assumptions:
- Developmentally, language develops in shapeshifters in a similar manner to humans (in terms of age-related milestones in language development).
- The switch typically happens between early and late childhood. More ambitious shapeshifters would go for younger babies, whereas more cautious ones would go for children who are old enough to walk independently (to swap younger children would involve sneaking into dwellings, whereas older children could be lured away).