Spiel
Etymology
From German "spielen" ("to play") and "Spiel" ("a game, a play"), carried into American English by way of Yiddish in the late 1800s. The idea of "playing" — as one plays music or a role — became the idea of reeling off a smooth, performed patter, especially the carnival barker’s or salesman’s. The performance sense is baked in: a spiel is a routine you play.
noun · /SHPEEL/
A glib, well-rehearsed speech intended to persuade, sell, or explain.
What it names
The practiced patter — the pitch someone can deliver on autopilot, whether a salesperson’s or your own oft-repeated explanation.
Example
I have my whole onboarding spiel down to four minutes now — I could give it in my sleep.
Related idea
A pitch aims squarely at making a sale; a spiel is the broader practiced patter, which may inform or entertain as much as sell.