Because they don't know the words.
Because you already know who it's isss! My little sister told me this joke.
Gives 'em something to do on Saturday night!
You can tune a guitar but you can't "tuna"fish!
Formed a coustic d'tat
He was afraid that he would swallow his words.
Four. O, double-u and e.
It's because they don't know the words.