In Celtic music, it is called “folderol”, and the Irish used them a lot in their music. Example: “Cumma ring ding diddle iddle i-di-o”.

“My Way” is the most popular and most requested song by beer drinkers in karaoke bars. Too much drink makes a person fuzzy in the head and up to a point that the person is rendered temporarily insane. So, when 2 or 3 drunkards meet, because of this temporary insanity, they burst out disagreeing with one another ultimately ending either in fist fights or duel to the death. Probably, as this incident occurred, the song “My Way” was playing and being sung. It was not actually the song that started the trouble but it was just unfortunately at the most inopportune time that it was being sung.

It’s just “filler”, like tra-la-la or la-di-da.

But so distinctively Sinatra, don’t you think?

A scat is vocalized either wordlessly or with nonsense words and syllables (e.g. “bippity-bippity-doo-wop-razzamatazz-skoobie-doobie-bee-bop-a-lula-shabazz”) as employed by jazz singers.

“Do be, or not do be do be do”