read someone's lips
US /riːd ˈsʌm.wʌnz lɪps/
UK /riːd ˈsʌm.wʌnz lɪps/
1.
to understand what someone is saying by watching the movements of their lips, without hearing their voice
:
•
The music was so loud, I had to read her lips to understand her.
•
He couldn't hear me over the crowd, so I just pointed and hoped he would read my lips.