Pronunciation Pontifications, Part 5

You don't say "all of THE sudden".

You say "all of A sudden".

It's an idiom, no rhyme or reason for giving the phrase all of a sudden a certain meaning, but that's what it's always been.

It's like saying the phrase "by the skin of my teeth" as "by a skin of and teeth". It just isn't how you say it. You sound a fool. And no one wants that.