After singing the prescribed zemiros each Friday night, the Skulener Rebbe was wont to sing just the niggun of the zemer without saying the words.

He explained that when you sing the words of a zemer, you are limited by the fixed text.  But singing a wordless melody is on a higher level – on the wings of a niggun, unencumbered by specific words, your feelings soar to the loftiest spheres. ~Hashabbos Noam Haneshamos as quoted by R’ Dovid Meisels