spruik /sprook/ (verb intr.) - To make an elaborate speech, especially to attract customers.
"The company's president appeared in the first of 80 television commercials spruiking a money-back guarantee if people disliked their new product."
Poet Carl Sandburg once described slang as "a language that rolls up its sleeves, spits on its hands, and goes to work." Nothing wrong with words in tie and suit but sometimes only slang can do the job. Since slang is often born in the back-alleys of language rather than in a sanitized hospital room, it's not easy to pin down its origins. Hence today's word, spruik, whose true origins are rather shrouded in mystery.