cat got your tongue, has the

Why are you silent? According to Eric Partridge, this term dates from the mid-nineteenth century in both England and the United States and was one of several phrases used in addressing a child who, after getting into trouble, refused to answer questions. The literal meaning is quite far-fetched, so it obviously comes from the grown-up’s invention of some bizarre circumstance that prevents the child from speaking. There is an analogous French idiom, “I throw [or give] my tongue to the cat,” meaning “I give up; I have nothing to say.”