Could someone get rid of a lisp as an adult?

Difficulty with S &: Z phonemes at the beginning, middle &; end of words constitute a lisp. Speech therapy & lots of practice smiling as you talk to yourself in a mirror can greatly reduce or eliminate a "permanent" frontal or interdental lisp, but may not be quite as effective for a lateral or palatal lisp. If you have a tongue thrust, your dentist may be able to insert an oral appliance that helps, also.