Good or bad? Schizophrenia is not good or bad. One is born with the trait and environmental factors and growing up allows it to express when it manifests itself with symptoms and signs. There is no reason to judge good or bad. One is born with it and learns to cope and live with the help of medications and psycho-social support.
Speech okay. Schizophrenia does not affect one's ability to speak, but it can and often does strongly affect the ability of others to understand what someone is saying--not because they are speaking poorly but because they are thinking illogically and may be saying things that make perfect sense to them but no sense at all to others. This can range from mild jumps in logic to what is called "word salad.".