Elijah Wald talks about folk icon Dave Van Ronk, whose memoir served as source material for the new Coen brothers film.

Long before rap, there was “the dozens” – the African-American street rhyming tradition that author Elijah Wald defines as “halfway between ‘yo mama’ jokes and rap freestyle battling.” He joins us to share the surprising musical history of the R-rated comedic insults.

Late last month, Mexican singer Sergio Vega was found shot to death on a highway in Sinaloa. No official motive has been determined, but many are speculating he was killed because of his music. Vega was a singer of “narcocorridos” – Mexican ranchera songs with lyrics about the drug trade – and he’s only the latest of a dozen such singers to be murdered in recent years.

Last week, Soundcheck discussed the theory that Robert Johnson’s iconic recordings are actually at the wrong speed. After receiving a flood of thoughtful comments from listeners, we revisit the topic today.