In the way of country music I think 'A Boy Named Sue' by Johnny Cash is a good example of the pre rap music. It was recorded live at San Quentin prison in '69. It's actually a poem by Shel Silverstien.
http://www.youtube.com/watch?v=X-hYLL7Gpos
From humble beginings.
The move from disco made an official rap genre in the late seventies, and it became popular in the early eighties (much to my disgust) but I recall one particular artist who I dare say was the fore father of rap music. The Grand Master Flash. Released in '81 I think.
http://www.youtube.com/watch?v=O4o8T...eature=related
Surely you know that one.