The results can be dramatic. Steve who is a chef now makes a living training other chefs. Something that his stuttering prevented him from doing in the past. The other main approach to stuttering is behavior modification. As the name implies, this therapy tries to control behaviors that contribute to stuttering.
People can become more comfortable with their stuttering.
They can become more easy to talk. So there recovery from the problem is quite possible. But there approaches while helpful to many don't always work. Jim Spurlock stuttered for thirty years. After trying everything else, he has now turned to an experimental drug treatment.