English: Can you attach your seat belt?
French: Pouvez-vous attacher votre ceinture (de sécurité).
Sometimes, you'll need to remind a passenger to buckle their seat belt for takeoff or landing or turbulence.
"Attach" is "attacher" in French. "Buckle" is "boucler". In English, we can use both words to convey more or less the same idea. Likewise, in French, we can also say "pouvez-vous boucler votre ceinture de sécurité?"
"Ceinture" (f) simply means "belt". A "seat belt", such as those found in a plane or a car, is "ceinture de sécurité" in French, literally "belt of security".
In English, flight attendants need to say "seat belt" and not just "belt". However, in French, we can simply say "ceinture"-"pouvez-vous boucler votre ceinture SVP?" and it'll be clear from the context that you're referring to their seat belt, and not the belt of their pants.
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