I've noticed that in some websites the expressions "adapted from traditional song" and "adapted from traditional story" are used.
Considering that "song" and "story" are singular nouns, I would consider that those expressions are wrong, I would use the article "a" before.
Is there a reason why those expressiona are used?
"Adapted from traditional music/dance/song" make sense.
The phrase with 'story' sounds odd though, and a Google search doesn't offer much evidence for it (3 hits on my server)
"Adapted from traditional narrative / oral history" would be alright.