could talk under water
Is always very talkative. Primarily heard in Australia. Good luck getting a word in if you invite Carrie—that girl could talk under water!
can talk under water
mainly AUSTRALIANIf you say that someone can talk under water, you mean that they talk a lot. My friends tell me that I can talk under water. What they didn't know was that she can also talk under water with a mouth full of marbles.