Traditional folk music belongs to an oral tradition: ancient music created, passed on, and developed through 'word of mouth' by generations of anonymous performers. It cannot usually be attributed to a single composer, but evolves from performances given by many musicians over time.
During the 19th and 20th centuries however, composers belonging to the classical tradition, such as Dvorak, Vaughan Williams and Bartok, used folk music to successfully inspire their own compositions. Bartok's 'Folk Dance': Mvt. III from his Dance Suite is one example of this.
Listen to Bartok's 'Folk Dance' and, following his example, compose your own 'Folk Dance', borrowing features from the folk music you have studied.
Bartok Dance Suite Mvt. III 'Folk Dance' Audio (Complete)
Bartok Dance Suite Mvt. III 'Folk Dance' Audio (Extract 0-42s)
Bartok Dance Suite Mvt. III 'Folk Dance' Score
Bartok Dance Suite Mvt. III 'Folk Dance' Video