Please switch off your mobile phones.
SPEG-ne-re — stress on first syllable. The 'gn' sounds like 'ny' in 'canyon'.
This is a phrase you will hear from cinema staff or see on screen before the film. Knowing it helps you understand the announcement. You can also say it to remind a companion.
'Si prega di' (literally 'one is asked to') is a formal impersonal construction used in public announcements. 'Spegnere' (to turn off/extinguish) applies to phones, lights and fires. 'Cellulare' (mobile phone) is the Italian word — 'smartphone' is also widely used.
Per favore metti il telefono in modalità silenziosa.
Please put your phone on silent mode.
Direct informal request — 'modalità silenziosa' = silent mode.
Vietato usare il cellulare in sala.
Mobile phone use is not permitted in the screen.
Prohibition sign language — 'vietato' = forbidden.
Puoi mettere via il telefono?
Can you put your phone away?
Said to a companion who is using their phone during the film.
Phone use during Italian films is taken seriously. Unlike some cultures where dim phone light is tolerated, Italian cinemagoers are generally intolerant of phone screens during screenings and will speak up.