style is important,lets take melodies ,most english irish scottish traditional melodies are in 4 modes.
spanish traditional melodies use different modes again, arabic traditional melodies different modes again.
very often traditional music does not modulate [change key].
but some modern songs that do sound traditional sometimes modulate when it comes to the chorus.
as regards lyrics,traditional songs seem to encompass a whole range of different subjects.
very often traditional songs can be sung successfully on acoustic instruments or unaccompanied,whereas some pop songs and all electronic songs ,and some songs that need amplification do not seem to work,without the electronic /electric devices[tremolsticks wah wah pedals etc]