read someone's lips

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Lip reading

read someone's lips (third-person singular simple present reads someone's lips, present participle reading someone's lips, simple past and past participle read someone's lips)

To discern what someone is saying by watching the shape of the mouth rather than by hearing the sounds of the words.
Deaf people may be able to read people's lips, but it's not a foolproof means of communication.
(idiomatic) To pay close attention (often imperative).
Read my lips. We are not going to the park today, and that is final.

discern what somebody is saying

English