There's a multitude of speech disorders, apraxia probably being one of the more severe. I, personally believe that they are neurological in why they exist. Two of my sons have had extensive speech therapy through the school system that started with early intervention recommended by their pediatrician. One of the two continues with speech in the school and I've had a change in health insurance and have been encouraged to try again for outside services.

I'm not so sure what Jojo has specifically.