Q: I have a student who has been in therapy for /s/ for a while now and, although he is able to produce the /s/ sound, his mom thinks it is now too sharp and unnatural. Do you have any advise for this?

When we are talking about refining an /s/ like you describe, this all auditory work combined with subtle tongue, lip, and perhaps jaw changes. This is the essence of articulation refinement for all phonemes for all clients. Van Riper called it “sound approximation” or “shaping”.

Usually a sharp or whistling sound means that the client is squeezing too hard, or lifting the tongue too near the palate at the tip. He probably is making too narrow of a channel for the airstream.

Have the client make his error sound. Then tell him to move the tip of his tongue slightly – millimeter by millimeter – until it sounds right to you and to him, and perhaps to his mom. Have him lift-or-lower the tip, or pull-back-or-push it forward. This is very subtle work done one millimeter at a time.

Do the same with the lips if necessary and the jaw if necessary. This is all a matter of trial and error. Make a tiny movement adjustment… listen… then adjust some more… listen again… adjust some more… and so forth. Do this until it sounds the way you want it to sound. Ask the client “How does that sound to you?” … “Does that sound right to you?” … “How about now?”

Make sure to take the position of the teeth into consideration. Then teach the client to listen carefully to his new sound. Teach him to achieve it consistently.

Also, sometimes straws of various diameter, from very wide (milkshake straw) to very narrow (coffee stirrer straw) will help the client conceptualize the diameter of the air channel.