These are all border ballads from the Medieval Era in England. As such, they were probably originally sung and not written, as they were meant for the (illiterate) common folk. In general, ballads will use simple language and short lines, making them more easily understood by all. They also use dialect, rather than formal language, to appeal more to the lower classes. Ballads (these included) will use repetition to further stress the importance of certain ideas, events and characters and to make them easier to remember and repeat. They are generally about sensational crimes, the struggles and hardships of working class life, the often-tragic fate of lovers, or historical disasters; these are all topics to which most people in the lower classes of Medieval England could relate.
In this era, the literature that appeal to the elite were high romances about the deeds of knights and damsels in distress. They praised lofty ideals and used more formal and flowery language. Ballads tend to much simpler.