read someone's lips
US /riːd ˈsʌm.wʌnz lɪps/
UK /riːd ˈsʌm.wʌnz lɪps/

1.
leggere le labbra, capire dal labiale
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.
La musica era così forte, ho dovuto leggere le sue labbra per capirla.
•
He couldn't hear me over the crowd, so I just pointed and hoped he would read my lips.
Non riusciva a sentirmi a causa della folla, così ho solo indicato e sperato che leggesse le mie labbra.