Is it true that being monotone is a sign of intelligence?

So my friends have told me on more than one occasion that I sound monotone when I speak (these guys aren’t too smart). And another one of my friends told me last night being monotone is a sign of intelligence (this friend I can have pretty intelligent conversations with). I’ve been searching everywhere online and I can’t find a thing about people being monotone and how high their intelligence is. But from what he told me and from what I can remember it’s because there’s a connection in your brain that that doesn’t signal how your voice pitch should be so all that attention goes and supports another part of your brain. So can anyone tell me if this is true or not, because I love learning new things about human anatomy.