In 1920's/30's Poland ther was a move to tidy up the presentation of traditional singing to suit more genteel tastes of the more western-tuned elements of society. The village women (and presumably men) were given courses on how to bow and perform. In some cass the keys and styles of singing were modified to be easier on the ear.

Most of that is now considered "the tradition" and it is very hard (if not impossible) to find (original) people who sang/sing in the earlier styles.