How does that make sense???

How does that make sense??? So you're telling me that when I sing, read aloud, talk to myself or my pets, I don't stutter, perfect fluency. But when you add another human being in my vicinity, I simply can't speak properly. You know? Precisely at the occasion for which we developed the ability to speak? Are you telling me that I have the ability to be fluent inside my brain, and it arbitrarily fails me at the moment that matters most? Yeah, right No one will convince me that this isn't a curse.