“We will be descending shortly into Denver," says the flight attendant, sounding very weird.
People who have to repeat announcements by rote—including radio station-break announcers and others—often try to avoid sounding like monotonous robots by raising and lowering the pitch of their voices at random and stressing words not normally stressed: mostly prepositions and auxiliary verbs.
One has to sympathize; imagine having to repeatedly lecture a plane full of people on seat-belt use when you know for a fact the only adults on board likely not to know already how to fasten a buckle are too demented to understand what you’re saying.
But the absurd sing-song into which many of these folks fall is both distracting and irritating, making them sound like malfunctioning robots.
Those who speak in natural voices, stressing main nouns, verbs, and adjectives where it makes sense, are much easier to listen to.