Cat got your tongue?
This expression has given rise to many fanciful origins ranging from eastern despots feeding the tongues of their victims to cats, to nautical tales of the cat o’nine tails as shipboard punishment. None are convincing, especially when the OED informs us that its first appearance in print was 1911. The expression is often used to admonish a child for not owning up to something and is therefore more likely to derive from the habit of cats bringing insects or small animals into the house, which may have caused speechlessness in children. This is only a theory, however, as the exact origin remains obscure.