Why do schizophrenics mumble to themselves?

Not all schizophrenics mumble to themselves. The belief that schizophrenia causes people to mumble to themselves is a common misconception. While it is true that some people with schizophrenia may experience auditory hallucinations, which can cause them to talk or shout to themselves, not all people with schizophrenia experience this symptom. Schizophrenia is a complex mental illness that affects each person differently, and its symptoms can vary greatly between individuals.