All of what you're describing is stuttering. The precise timing and coordination required for speech starts in the brain. Stuttering is far more than just a speech problem. The region of the brain that stuttering originates from is defective in stutterers. It's even been tested (though not necessarily conclusively) that stutterers do worse in rhythmic activities not involving speech due to this physical brain defect. At the same time, we score much higher in IQ tests than the average person who doesn't stutter. We're definitely wired differently. That part took me a bit to accept as well. But it's okay. There's nothing wrong with us. We're just different.