This advice-column-style blog for SLPs was authored by Pam Marshalla from 2006 to 2015, the archives of which can be explored here. Use the extensive keywords list found in the right-hand column (on mobile: at the bottom of the page) to browse specific topics, or use the search feature to locate specific words or phrases throughout the entire blog.
Most therapists would not treat a lateral lisp in a 3-year-old, but one could, and some do.
Use the “Long T Method” and make it playful. Hold one end of a straw in front of the central teeth and have the child make a T. The airstream should go into the straw and amplify. Now make it “longer” — aspirate it. It won’t sound like “S” but it will sound like a “Long T.” Call it the “Snake Sound.”
Have fun with the snake sound–– “Oh no! I hear a snake… The snake is coming… The snake is hissing… He’s in your mouth… He’s going into the straw…” 🙂