I've always been a big fan of ska and reggae (as is evidenced here). Jamaican music went through numerous changes over the years, including the dub years, which is how reggae music spent the 1970's. Dub consists of a sparse, minimal, bass heavy groove, likely fueled by marijuana intake of studio musicians.
Talkover was a component of Dub, but actually had it's roots in the 1950's. Talkover consisted of a reggae DJ playing the instrumental (or 'version' as it came to be known), and saying nursery rhymes over the music. It was much more of a live experience than most other Jamaican music, and didnt translate to record too well. Some artists who made a career of sorts out of it were names like Dennis Al Capone, i Roy, and the legendary King Stitt.