"Is is"

People unnecessarily start sentences with "so" a lot. Particularly math professors. This is a funny quirk. Is it a nerd thing? Maybe when you get all mathy and intellectual, you find the need to pause before sentences to make sure your sentence is logical. I hear you there; I do that too. You don't hear carefree happy-go-lucky folks saying "so" a lot.

Here is another funny quirk. Sometimes people say "is is" when they mean "is." For example, overheard just now:
"My concern is, is that..."

What! Why do you do that?! Why doesn't anyone ever notice? This is really strange!