The resting position of the tongue during childhood is more than a speech concern. It is one of the key forces that shapes how the jaw and palate develop over time.
Short answer
Proper tongue posture means the entire tongue rests against the roof of the mouth — the palate — with lips closed and teeth lightly touching. This posture applies consistent upward and lateral pressure to the upper arch during growth, supporting its width and shape. When the tongue rests low in the mouth — typically associated with mouth breathing — this developmental stimulus is absent and the arch may narrow over time.
What is proper tongue posture?
Proper tongue posture means the tongue rests gently against the roof of the mouth — the palate — when the mouth is closed and the child is at rest. The tip of the tongue should sit just behind the upper front teeth, with the body of the tongue making broad contact with the palate. This position supports nasal breathing and provides the internal pressure needed to shape the developing jaw.
This resting position is sometimes described as "mewing" in popular discussion, but in clinical terms it reflects the natural, functional position the tongue should occupy when the airway is unobstructed and the lips are comfortably closed. It is not a deliberate exercise — it is where the tongue should be habitually, at rest.
Why tongue posture matters
The tongue is the primary internal force acting on the upper jaw during growth. When it rests correctly against the palate, it provides continuous, gentle outward pressure that supports the development of a wide, well-formed arch. The palate responds to this pressure over time, developing the width needed to accommodate teeth and allow adequate space for nasal airflow above.
The palate forms the roof of the mouth and simultaneously the floor of the nasal cavity. A well-developed, wide palate supports better nasal breathing. A narrow palate reduces nasal airway space — which may contribute to nasal congestion, mouth breathing, and related airway concerns.
Tongue posture also influences the lower jaw. When the tongue habitually rests low — on the floor of the mouth rather than the roof — it changes the balance of forces on both arches and may contribute to narrower development over time.
What happens with low tongue posture
When the tongue rests on the floor of the mouth instead of the palate, the upper arch loses the internal pressure that supports its development. The cheek muscles exert inward pressure on the arch without the counter-pressure of the tongue, and the palate may develop more narrowly as a result.
A narrower upper arch means less space for teeth — contributing to crowding — and less volume in the nasal cavity above. This may make nasal breathing more difficult, which in turn encourages more mouth breathing, which further reduces the tongue's contact with the palate. The pattern can reinforce itself over the course of childhood.
Low tongue posture is often associated with mouth breathing rather than being an independent cause. The two tend to occur together, and addressing both as part of a growth-centered evaluation is more informative than looking at either in isolation.
Signs of poor tongue posture
These signs may suggest a child is not habitually resting the tongue against the palate. They are worth noting alongside other growth and breathing observations.
- Mouth breathing — A child who breathes through the mouth at rest — during sleep, quiet activities, or the day — is unlikely to have the tongue resting against the palate at the same time. Mouth breathing and low tongue posture tend to occur together.
- Open lips at rest — Lips that rest apart rather than together, without active opening, may reflect an oral breathing pattern and low tongue resting position.
- Narrow palate — A V-shaped or narrow upper arch is one of the most visible signs that the internal forces shaping the palate may have been insufficient during growth. This can be observed as a narrow smile or crowded teeth.
- Speech issues — A lisp or difficulty with certain sounds may be associated with atypical tongue position or function. This is not universal, but persistent speech concerns in a child with other signs may be worth evaluating together.
None of these signs alone is diagnostic. A pattern of several — particularly combined with crowded teeth or a narrow smile — may suggest the jaw and palate development is worth evaluating from a functional perspective.