Frontal Lisp/Interdental Lisp | Speech Therapy Ideas & Word Lists

What Is a Frontal Lisp?

Let’s start at the beginning. A frontal lisp, also known as an interdental lisp, occurs when a child says the /s/ and /z/ sounds with the tongue pushed too far forward. This causes /s/ and /z/ to sound more like “th”. Frontal lisps are sometimes caused by tongue thrust, which is when the tongue is consistently too far forward, including during swallowing and at rest (when the tongue is not doing anything at all). Not all frontal lisps are caused by tongue thrust but some are. Tongue thrust requires additional types of therapy that are not discussed in this article. Today’s article will just focus on treatment for a plain old frontal lisp.

Alternatively, there is another type of lisp called a lateral lisp.  This is where air comes out the sides of the mouth, making the /s/ and /z/ sounds “slushy”.  There is also often a lot of saliva associated with a lateral lisp.  For more information about treating lateral lisps, click here.

How Do You Treat Frontal Lisp?

I’m so glad you asked! Frontal lisp therapy can be broken down into six steps.

/s/ Articulation Worksheets and Homework

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1. Assessment for a Frontal Lisp:

The first thing you will need to do for frontal lisp therapy is to assess the lisp. You don’t need any standardized tests for this, you just need a lot of words for the child to say so you can see if there are any words where the child is already producing a good /s/ or /z/ sound. I recommend you test both the /s/ and /z/ in all word positions. This means testing when the sound is at the beginning, middle, and end of the word as well as in consonant clusters (blends) at both the beginning and end of the word.

Simply have the child say words with the sounds in all of those different positions. If the child can read, just have him read word lists. If the child cannot read, you can have him label pictures that represent the words. Below are my word lists for /s/ and /z/ in all positions, or you can download my articulation cards which contain pictures of /s/ and /z/ words in the initial, medial, and final position as well as /s/ blends in the initial position of words. Just write down which words the child can say correctly and which words are lisped.

Click Here to Download the /s/ and /z/ Artic Cards and Worksheets for Free!

Lisp Words: Word Lists for Assessing Frontal Lisps

Initial /s/

• Say
• See
• Siren
• Soap
• Soup
• Second
• Simple
• Sock
• Sad
• Soot
• Sun
• Sound
• Soy

Medial /s/

• Medicine
• Motorcycle
• Pieces
• Pacifier
• Castle
• Whistle
• Dinosaur
• Glasses
• Recycle
• Pencil
• Baseball
• Popsicle

Final /s/

• Base
• Crease
• Ice
• Close (like opposite of far)
• Moose
• “s”
• Kiss
• Boss
• Class
• Bus
• Mouse

Initial /s/ Blends

• Smile
• Smell
• Small
• Smooth
• Swing
• Sweet
• Swim
• Snake
• Snow
• Snack
• Sticker
• Stop
• Stairs
• Spoon
• Spaghetti
• Spider
• Strawberry
• Street
• stripe

Final /s/ Blends

• Coughs
• Laughs
• Forests
• Tests
• Claps
• Tips
• Wasps
• Asps
• Fox
• Mix
• Mask
• Whisk
• Asks
• Whisks
• Best
• Lost

Initial /z/

• Zebra
• Zoo
• Zipper
• Zap
• Zero
• Zig zag
• Zone

Medial /z/

• Puzzle
• Scissors
• Bulldozer
• Lizard
• Wizard
• Raisin
• Tweezer
• Desert
• Present
• Newspaper

Final /z/

• Maze
• Sneeze
• Eyes
• Nose
• Lose
• Fizz
• Jaws
• Fuzz
• Cows
• Boys

2) Find a Natural Tongue Placement to Eliminate Frontal Lisp

Ok, take a look at your results. Was the child able to say the /s/ or /z/ sound correctly in any of those words? If so, that’s where you’re going to start! Have the child say that word (or words if the child had multiple words he could say) and ask him to feel where his tongue is for the /s/ sound when he says it. Talk about how the tongue is behind the teeth. Ask the child to tell you if his tongue tip is up or down. Either way is acceptable and some children do it with the tongue tip up behind the top front teeth and some do it with the tongue tip down behind the bottom front teeth.

Make sure the child is saying the /s/ sound in the word in a very crisp, clear manner without any lisp. If he starts to lisp on it, try a different word. Practice this correct /s/ sound (in those words if necessary) until the child knows exactly what his tongue is doing. If the child does not have any correct productions after testing all of those words, you can either keep trying new words to try to find a good one, or try some elicitation techniques to get an /s/ without having a word that he can already produce correctly.

Elicitation Techniques for /s/ and /z/:

If the client is having a hard time getting a good /s/ placement, try some of these tips.  Watch the video below for tips for speech-language pathologists to help a child produce this sound.

Exploding /t/ Sound:

Start by having the child say the /t/ sound. Have him say it over and over again (“t…t…t..t…t”). Then, tell him that you want him to say it 5 times but explode the last one. Take that last /t/ and force it out as hard and long as you can. It should sound like this “t…t…t…t…tsssss”. You should get a nice /s/ sound after the /t/. Don’t tell the child that’s the /s/ sound right away.

Practice it a few times until you know he can do it and then say “Hey, that makes an /s/ sound at the end”. If you can get the exploding “t” sound, then you can practice it in words that end in “ts” like “bets” and “cats”. Or, you can practice holding out the /s/ part of it and then putting a pause in the middle of the /s/ so that the child gets practice starting the /s/ sound again, like “tssss…sssss”.

The Straw Technique for Teaching the /s/ Sound:

This is a great strategy for teaching the /s/ sound. Use a straw to get help the child keep their tongue back and blow the air right through the middle.

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Coarticulation:

Coarticulation is when you put a different sound next to the target sound so it comes out more clearly. In the above example, we used the /t/ to facilitate the /s/ sound because the /t/ sound is produced in the same place in the mouth as the /s/ sound. You can use coarticulation by saying a word that ends in /t/ right before a word that starts with /s/.

For example, you could say “cat soup” to try to get a good placement for /s/. You could also use the /n/ sound, like “tan silo” because the /n/ sound is also produced in the same place as the /s/. Or, you may find that other sounds work well to help the child say the /s/ or /z/ sound, such as sounds that require the tongue to be in the back of the mouth like /r/ (bear soup) or /k/ (black sock). Try a bunch of different sounds to see if any help.

Turning Voice on for /z/:

If you are able to get the /s/ sound but are struggling to get /z/, have the child practice turning his voice on by humming. Have the child place his hand on his throat so he can feel the vibrations when he turns his voice on and hums. Then, have him say the /s/ sound and then turn his voice on or hum. If he’s having trouble with this, have him hum a simple tune while saying the /s/ sound.

3. Eliminate Frontal Lisp in Single Words

Once you are able to get the child to say a good /s/ or /z/ sound (either in single words or by itself), you want to start working on saying that sound in single words. If you were able to get the child to say either /s/ or /z/ in one or more of the words from the assessment, start with those words and other words like them. For example, if the child was able to say “bus”, try other words that have the “uh” vowel and then the /s/ sound, like “us”, “Gus”, “Rus” (you may have to get creative). Then, slowly branch out to words that are slightly less similar. For this example, you could start trying other words with /s/ at the end but with different vowels.

If you weren’t able to get any of the words before but were able to get a good /s/ using the elicitation techniques, try having him put that good /s/ into some words and see what’s the easiest. For example, if you used the exploding /t/, you’ll want to start with words that have /ts/ in them. If you need to, go throu