The hidden impact of mouth breathing and open mouth posture on speech and feeding

When most people think about speech or feeding difficulties, they picture the tongue, lips, or chewing skills, but how a child breathes at rest plays a surprisingly big role too.

Mouth breathing and open mouth resting posture can quietly influence everything from how a child’s face grows to how clearly they speak, to how confidently they chew and swallow. It’s something many parents never think about, until they start noticing the subtle signs.

Let’s explore why this happens, what to look for, and how to gently support better breathing and oral posture.

Recent research supports this link between mouth breathing and speech difficulties. For example, a 2022 study by Alhazmi et al., published in the Journal of Pharmacy and Bioallied Sciences, found that 81.7% of children aged 9–17 who breathed primarily through their mouths presented with speech sound disorders. The study highlights how mouth breathing can significantly influence orofacial development and articulation patterns.

💨 Why we’re designed to breathe through our nose

Our bodies are made for nasal breathing. When we breathe through the nose, the air is filtered, warmed, and humidified before reaching the lungs. The tongue naturally rests against the roof of the mouth, the lips close gently, and the jaw stays relaxed, all of which encourage healthy oral development.

In contrast, mouth breathing often means the tongue rests low in the mouth and the lips stay apart. Over time, this posture can subtly reshape how the muscles and bones of the face grow.

Children who breathe through their mouths most of the time may develop:

• A longer face and narrower palate
• Forward head posture
• Slightly open lips and low tongue position at rest
• A tendency toward drooling or noisy breathing
• A dry mouth and consequently bad breath
• At times the tongue pushes constantly against the front teeth causing them to grow forward (buck teeth)

These changes are not anyone’s fault, as they often start because of blocked noses, allergies, enlarged adenoids, low facial muscle tone or habits formed when a child was younger. But understanding the pattern helps us know how to support change.

🗣 How mouth breathing affects speech

Speech depends on precise coordination between the lips, tongue, and jaw. The resting position of these structures affects how ready they are to move.

1. Reduced tongue strength and placement, i.e. the tongue rests low in the mouth (as it does in mouth breathing), it’s harder for children to lift it efficiently for sounds like /T/, /D/, /N/, /L/, and /S/. This can lead to speech that sounds slightly slushy or unclear, or a frontal lisp.
2. Open mouth posture and resonance: An open mouth at rest may affect how air vibrates in the oral and nasal cavities. Children might have speech that sounds a bit ‘muffled’ or lacks crispness because the lips and jaw aren’t fully supporting articulation.
3. Fatigue and breath control: Mouth breathing can lead to drier mouths and less efficient breath support. That can make longer sentences or conversations feel tiring, especially in noisy environments.

🥄 How mouth breathing affects feeding and chewing

Feeding involves the same structures that control speech, so posture and breathing patterns matter here, too.

1. Chewing efficiency: Children who habitually keep their mouths open often have low tongue tone and reduced jaw stability. They may prefer softer foods, chew slowly, or struggle with mixed textures.
2. Swallowing pattern: A tongue that rests low may push forward when swallowing. This ‘tongue-thrust swallow’ can interfere with efficient chewing and even affect dental alignment over time.
3. Breathing while eating: Since it’s hard to chew, swallow, and breathe through the mouth simultaneously, children who can’t comfortably nasal breathe may rush bites or pause to catch their breath. This can contribute to coughing, choking, or food refusal.

Common signs to watch for

Parents often notice subtle clues before realising mouth breathing is a pattern. Some red flags include:

• Lips habitually open at rest
• Drooling after the toddler years
• Snoring or noisy breathing during sleep
• Preference for soft foods or grazing eating habits
• Dark circles under the eyes due to allergies
• Frequent colds, congestion, or mouth odour
• Speech that sounds slushy or unclear despite good effort

If several of these sound familiar, it’s worth mentioning them to your child’s GP, dentist, or speech and language therapist.

👩‍⚕️ What can help

1. Address the underlying cause: If nasal blockage, allergies, or enlarged adenoids are making nasal breathing difficult, a medical assessment is the first step. ENT specialists can rule out or treat physical causes.
2. Encourage closed mouth rest: Gentle reminders like ‘Lips together, tongue up, breathe through your nose’ can help older children become aware of their resting posture. For younger ones, visual cues (stickers or mirrors) can make it a game.
3. Build oral-motor strength and awareness: Speech therapists can design activities to strengthen the tongue and lips, improve jaw stability, and encourage balanced breathing. This might include blowing games, tongue-tip lifts, use of dental-palatal devices or oral-motor exercises disguised as play.
4. Support good posture: Sometimes mouth breathing goes hand-in-hand with forward-head posture. Encouraging upright sitting during meals and screen time helps keep the airway open and supports better breathing habits.
5. Make nasal breathing part of daily routines: Gentle nose-breathing practice during calm times (reading, bedtime, car rides) helps normalise it. Avoid making it a battle: calm, consistent reminders work best.

🌱 A gentle note on change

Patterns of mouth breathing develop over time, and change doesn’t happen overnight. It’s important to approach this with curiosity, not criticism. The aim isn’t ‘perfect breathing,’ but to give your child the tools and awareness to breathe comfortably and efficiently.

Small improvements in nasal breathing and resting posture can lead to big gains in speech clarity, eating confidence, and even sleep quality.

💡 The takeaway

Breathing seems automatic, and it is! but how we breathe matters. Mouth breathing and open-mouth posture can quietly shape how a child speaks, eats, and grows.

By noticing early signs, addressing underlying causes, and building supportive habits, you can help your child move toward stronger, clearer speech and more comfortable mealtimes.

Just like every area of development, progress starts with connection, patience, and gentle consistency, one calm breath at a time.

Sonja McGeachie

References

Alhazmi, A., Alshamrani, A., Alhussain, A., et al. (2022). Mouth Breathing and Speech Disorders: A Multidisciplinary Study. Journal of Pharmacy and Bioallied Sciences 14(5):911. https://www.researchgate.net/publication/361978128_Mouth_breathing_and_speech_disorders_A_multidisciplinary_evaluation_based_on_the_etiology

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