Dentalized Lisp: When the Tongue Pushes Against the Teeth on S

What a dentalized lisp is

A clear S is made with the tongue tip just behind the upper front teeth, on the ridge, with a narrow groove that channels air against the teeth. In a dentalized lisp, the tongue tip moves forward and presses against the back of the teeth themselves. Phoneticians mark this with a small bridge under the symbol — [s̪] — the IPA’s diacritic for a dental sound.⁴

ASHA classifies errors like this as distortions: the sound is attempted but altered, rather than replaced by a different sound. Its own example of a distortion is a lateral /s/; a dentalized S is the same kind of error with the tongue too far forward.¹

Ages and when it matters

S and Z are acquired at 4;0–4;11 at the 90% criterion in US data, so a forward, imprecise S in a 3-year-old is common. A dentalized S that is still present in the school years is a residual error — the kind of distortion that, according to a 2015 review, persists in an estimated 1–2% of young adults.^3,5

Because the tongue stays behind the teeth, a dentalized lisp is less obvious than a frontal one, and parents often notice it only as an S that “isn’t quite crisp.” That subtlety is why a listening and visual evaluation by an SLP matters more for this type than for the frontal one.

What helps: the treatment evidence

Direct evidence is limited but encouraging. In a preliminary study of 18 children aged 6;9 to 11;10 with dentalized or interdental S and Z, once-weekly 10-minute individual sessions — phonetic placement cues to establish the sound, then concentrated drill moving into natural contexts — produced significant gains in spontaneous speech compared with a waiting group, and most children retained their accuracy two years later. The authors note that traditional methods for distortion errors in older school-age children have had mixed success.²

SLPs give visual and tactile information about tongue placement: ASHA lists using a mirror, tactile cues such as a tongue depressor, and technologies such as ultrasound and palatography that show where the tongue touches. What does not help: a systematic review found insufficient evidence that nonspeech oral motor exercises change speech.^1,6

Home practice

1. 1Find the spot. Tongue tip up to the bumpy ridge just behind the top teeth — not on the teeth. Use a mirror.
2. 2Teeth together, smile. Lightly close the teeth and spread the lips; this keeps the tongue back.
3. 3Push the air down the middle: “ssss.” It should sound sharp, like a snake or a tire hissing.
4. 4Move up the ladder: S in syllables, words, phrases, then sentences, practicing a few minutes most days.

If your child cannot find the sharp S even with a model, or the S sounds wet or slushy, see a speech-language pathologist — find one through ASHA’s ProFind directory. ASHA’s consumer page describes what an evaluation involves.^7,8

Frequently asked questions

References

8 sources from authoritative bodies. Last reviewed October 2026.

1. 1.ASHASpeech Sound Disorders: Articulation and Phonology — Practice Portal page.
2. 2.Peer-reviewedFlipsen, Sacks & Neils-Strunjas — Effectiveness of SATPAC to Remediate Dentalized and Interdental /s, z/ — Preliminary treatment study (Perceptual and Motor Skills), 2013.
3. 3.Peer-reviewedCrowe & McLeod — Children’s English Consonant Acquisition in the United States: A Review — Systematic review (AJSLP), 2020.
4. 4.International Phonetic AssociationThe International Phonetic Alphabet and the IPA Chart — Official IPA chart.
5. 5.Peer-reviewedFlipsen — Emergence and Prevalence of Persistent and Residual Speech Errors — Review (Seminars in Speech and Language), 2015.
6. 6.Peer-reviewedMcCauley et al. — Effects of Nonspeech Oral Motor Exercises on Speech — Evidence-based systematic review (AJSLP), 2009.
7. 7.ASHASpeech Sound Disorders — Consumer page.
8. 8.ASHAASHA ProFind: Find a Certified Speech-Language Pathologist — Referral directory.