(informal) look who's talking! you're one to talk! you can talk!

(informal, figuratively) to waste one's breath (to speak without being listened to) / (informal, figuratively) to blow smoke; to talk through one's hat (to speak about issues one doesn't understand)

(literally) to speak too fast / (figuratively) to speak too soon

to speak for oneself

(figuratively) to talk under one's breath, to mutter, to mumble

(figuratively) to talk under one's breath, to mutter, to mumble

to set tongues wagging, to make waves, to hit the headlines, to get oneself talked about, to be the talk of the town

(figuratively) to speak to someone who doesn't listen; to preach to deaf ears

(informal) to get an earful, to be scolded

(simile) to talk like a book