Folk

Folk music is simple, acoustic-based music that turns everyday events and common people into something almost legendary (AllMusic, n.d.-g). Most countries have their own version, but as a genre label it usually points to American and British music passed down through generations by word of mouth rather than sheet music (AllMusic, n.d.-g). Think of it like a family recipe handed down by memory instead of a written cookbook. Nobody wrote the original instructions, and the dish changes slightly with every generation that makes it.

That oral tradition is central to how folk music is defined. Wikipedia describes traditional folk music as music transmitted by ear, with unknown composers, played on traditional instruments, and tied to a people's cultural identity or folklore (Folk music, n.d.). Because there is no fixed, published version, a folk song can shift over time as it passes from person to person, a process sometimes called the "folk process" (Folk music, n.d.).

In the United States, folk music has roots in several traditions, including the work songs of enslaved West Africans, which used call and response and later shaped gospel and blues, and British and Irish ballad traditions that told stories through song (Folk music, n.d.). Most early recorded folk music followed this pattern of anonymous, evolved songs, but that began to shift with Woody Guthrie, who helped bring topical, politically minded songwriting into the genre (AllMusic, n.d.-g).

That shift eventually led to what is called contemporary folk music, or the folk revival, which took off in the mid-20th century and peaked in the 1960s (Folk music, n.d.). Artists like the Weavers and Pete Seeger mixed traditional songs with new material, and Bob Dylan pushed the change even further. By his second album, he was writing almost entirely original songs, which set the template for modern folk, personal and introspective songwriting, with only occasional covers of older material (AllMusic, n.d.-g).

Sources:

AllMusic. (n.d.-g). Folk music genre overview. https://www.allmusic.com/genre/folk-ma0000002592
Folk music. (n.d.). In Wikipedia. https://en.wikipedia.org/wiki/Folk_music