The roots of all branches of folk music are similar: largely Southern, mostly rural and religiously influenced. The Rolling Stone History of Rock & Roll determined that "rock & roll was an inevitable outgrowth of the social and musical interactions between blacks and whites in the South and Southwest."
With the advent of radio, the exposure and popularization of black Southern spirituals, white Southern country & western and New Orleans blues musicians began. The exposure the radio and record industry brought to folk music had a greater influence on this genre than any other of its era. Previously limited to the community in which the songs and styles were born, the airwaves allowed musicians from other parts of America to hear the guitar riffs and vocal inflections other acoustic musicians were applying to traditional and new songs.
At the turn of the 20th Century, a new type of music emerged from the South known as "One-verse songs". The vocal form based on the folk narrative of southern plantation songs, was matched with great improvisation and a heavy--almost emotional--harmonic line. The style was the Blues, a combination of dramatic gospel hymns and tortured slave emotion singularly referred to as southern slave music.
The Blues remained "underground" from popular music until 1912 when W.C. Handy published "Memphis Blues". Handy was the first African American publisher of his own material and became known as "The Father Of The Blues." Even though popular music did not fully recognize the Blues until the middle of the 1920's, the music is considered to be the one truly American genre with the richest history from which all other types of American music sprang. It was the harmonic foundation for Jazz and later it was the emotional inspiration for rock n' roll.
White folk music began with the Colonial interpretation of the English, Scottish and Irish dance music. In the new country the dance music relied heavily on the fiddle and was later joined with more percussive instruments, such as the tambourine and the banjo, adopted from plantation work songs. White Folk music was traditionally passed on by oral tradition, until the first recordings in 1920 by Jimmie Rodgers and the Carter Family. This new sound was decidedly "country & western".
The pioneers of folk and blues music set the ground work for what would later be R& B, Western swing, country music and the singer-songwriter.