The Biggest Mistake I Made in Speech Therapy When Correcting a Lisp

I sat there wondering how to correct a lisp…

“Okay, hide your tongue behind your teeth,” I suggested. I was sitting in another speech therapy session with a student, trying to correct a frontal lisp. Unsuccessfully, I might add.

“Thhhhhhhh,” was the response. Well, to be fair, my student HAD put his tongue behind his teeth. My directions had been followed, to a tea. The result was a “dentalized” /s/. I’m not sure If that’s a real term, but I think get you get the idea. Basically, a voiceless “th” that was stopped by the front teeth. 

This is the exact part of the movie where the director would yell, “CUT!” 

Seriously though, face palm. There is nothing more frustrating than trying to correct a frontal lisp or a lateral lisp (or if we want to be realllllly specific here, an interdental lisp, addental lisp, lateral lisp, strident lisp, or palatal lisp… but more on that later). And I was a new SLP, desperately wanting to figure out this “correcting a lisp thing”.

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Types of Lisps

Facebook groups, Google, and colleague’s advice had all let me down. I wasn’t quite sure why at the time, but now that I have…literally… studied all things lisps (frontal lisps, lateral lisps, EVERY TYPE OF LISP), I understand that I was a) not being specific enough about HOW and WHERE to move the tongue and b) skipping foundational things.

The importance of establishing normal resting posture before even working on speech was drilled into me when I took orofacial myology training, and that deserves a post of its own. 

Right now, though, I just want to talk about how I specifically explain WHERE and HOW the tongue moves to my students when I AM working to establish /s/ in isolation.

AKA, why my “hide your tongue” statement really didn’t work. There’s a lot of reasons it didn’t, so let’s dig a little deeper to find out why.

For a “typical” /s/ and /z/, your tongue tip can be UP or DOWN. However, the sides of your tongue must be elevated, and they need to touch the sides of the top teeth Basically, you need a way to funnel the air forward and out.

So knowing THAT, we can then think about where we are trying to get our students to place their tongues. 

When we understand what TYPE of lisp they have, we can give better directional cues.

Reference: Articulatory and Phonological Impairments: A Clinical Focus, Third Edition. By Jacqueline Bauman-Waengler

Interdental Lisp

When your student is demonstrating an interdental lisp (frontal lisp), the tongue is forward and between the teeth. The result sounds like a “th” for an “s”. It would be like your student is saying “think” for “sink”.

Addental Lisp

I sometimes call this a “dentalized lisp”, but not really sure if that’s a real term. When this is happening, you aren’t seeing the tongue between the teeth like you are for an interdental lisp. Instead, the tongue tip is touching the back surface of the teeth (or at least it is too far forward), and the edges of the tongue are flat.

Lateral Lisp

When your student is demonstrating a lateral lisp, the sides of his/ her tongue are flat- and because the sides aren’t lifting, air is flowing freely into the cheeks. When that escaping air mixes with saliva, it results in a “slushy” sound.

A lateral lisp can be bilateral or unilateral (meaning air may be escaping on both sides or one side).

I read an old articulation text book once- and Hilda Fisher described a lateral lisp as a “slushy L”. That made complete sense to me.

Palatal Lisp

When your student has a palatal lisp, the tongue tip is too far back- it’s in the palatal area. The resulting sound would be more like a distorted “SH” instead of “s”.

Strident Lisp

This is when /s/ sounds “whistle-like”- and it’s because too much airflow is being pushed through a narrow opening.

Explaining Tongue Movement

“Hide your tongue.”

I think this is a common thing that is said to students when correcting a lisp- but hopefully the information above will detail why I don’t think this will result in a crisp /s/ or /z/.

The truth is, “hiding the tongue” will probably place the tongue directly behind the front teeth- and that’s going to result in an “addental” production of /s/. This has been my clinical experience.

Instead, I’d recommend trying to figure out what type of lisp your student has, so that you can better direct them to move their tongue to the right area.

“Oops- I heard slushy air. Make sure to lift the sides of your tongue,” I might tell my student who is demonstrating a lateral lisp. I know the “tunnel” wasn’t working, because air flowed freely into the cheeks.

“Try moving that tongue tip up just a little,” I often say to my student demonstrating an addental lisp.

“Move your tongue tip in and UP towards home,” I might direct my student with an interdental lisp. “I saw your tongue come between your teeth!”

“Slide your tongue tip forward, towards home (the alveolar ridge), just a little,” I could suggest if my student is demonstrating a palatal lisp. “It’s too far back.”

And if my student is demonstrating a strident lisp? “Oops, just a little too much air. Can you try it again, but be a little more gentle? Like… this?”

My favorite tools for correcting a lisp

There are certain tools I find incredibly useful when trying to correct a frontal lisp or a lateral lisp.

As I mentioned earlier, one of my main objectives is establishing the correct lingual resting posture. To do this, your student really needs to understand the “basics”- including where “home” (aka the alveolar ridge) is located.

My suggestion is to have a typodont on hand.

This allows you to simply point to a model, so your student can easily visualize where to place the front part of the tongue while at rest.

An additional item you’ll want to have on hand is a mirror. Ideally, you would want something small with a stand that can be positioned on your desk. This would allow your student to easily move it while trying to focus on lingual movement and positioning.

Finally, you’ll absolutely want to check out my Correct that Lisp resource on TpT!

This is a clear, step-by-step program that will provide guidance for you as you treat lateral lisps or interdental lisps.