fitting the flaps
n.— «Lip Synchronisation, known in America as “fitting the flaps,” is a means of ensuring that the sound of the words being spoken matched the lip movements of the onscreen speaker.» —“Lost in Translation” Schoolgirl Milky Crisis Nov. 27, 2006. (source: Double-Tongued Dictionary)
Further reading
Is there such a thing as a “neutral” accent, and if so what does it sound like? And that quirk in the way southern Californians talk about freeways. They’ll say things like take the 405 and get on the 8. Why the definite article...
La verdad de la milanesa, literally “the truth of the milanesa,” is an Argentine Spanish expression meaning “the real truth.” One possible origin involves a dispute over whether the breaded meat dish milanesa comes from Italy or Austria. Another...