Heart in one’s mouth

To have one’s heart in one’s mouth is to be extremely fearful or anxious. It is a very old expression and although Shakespeare uses it in King Lear Act I, Scene I, when Cordelia says, “Unhappy that I am, I cannot heave my heart into my mouth.” Shakespeare did not coin the expression. The earliest known citation appears in Latin, the Satyricon written by Gaius Petronius who died c. AD 66, “My heart was in my mouth.”