Just like how a stutter is extremely hard to cure because it’s neurological. It seems like you’re making false assumptions to justify your case and get pity points. I do research on lots of conditions. And a lisp is very easy to cure, even in adult hood since it’s technically a habit you developed. You could literally do exercises at home. A stutter is neurological. You physically have a hard time getting those words out. Even with the most powerful speech therapy, stuttering is life. And it could all of a sudden one day relapse. And I don’t know what makes you think that stutterers speak clearly, since it’s a fluency disorder, which means we can’t exactly speak clearly.