If your teeth or jaw have not developed as expected, you may find certain sounds more difficult to pronounce clearly. While many speech problems improve with treatment or therapy, some people benefit from assessment by a dentist, orthodontist or speech and language therapist to identify the underlying cause.

Why do teeth and jaw development affect speech?

Speech is created by a combination of airflow, the vocal cords and the movement of your tongue, lips, teeth and jaw. These structures work together to produce different sounds.

For example, sounds such as "s", "z", "f", "v", "th" and "sh" rely on the tongue making precise contact with the teeth or the roof of the mouth. If the teeth are crowded, widely spaced or positioned differently, it can change the airflow and make these sounds less clear.

Similarly, the position of the jaw affects how easily the tongue and lips can move during speech. If the upper and lower jaws do not meet properly, some sounds may be distorted or require extra effort to produce.

Which dental problems can affect speech?

Several dental conditions can influence speech development and clarity. One of the most common is a large gap between the upper and lower front teeth, known as an open bite. This often allows too much air to escape when speaking, making sounds such as "s" or "z" sound like a lisp.

Overbites, underbites and crossbites can also affect how the tongue contacts the teeth during speech. Missing teeth, particularly the front teeth, may temporarily change the way certain sounds are pronounced.

Crowded teeth can reduce the available space for the tongue, while very protruding teeth may alter lip position and airflow during speech.

Research suggests that around 20–30% of children develop some form of speech sound disorder during early childhood, although many improve as they grow. Studies have also found that children with significant bite problems are more likely to experience speech difficulties than those with normal dental development.

How can your teeth affect your voice and singing voice?

Your teeth can influence both your speaking voice and your singing voice because they help shape the sounds that leave your mouth. The position of your front teeth affects how air flows and how clearly consonants such as "s", "f", "v" and "th" are produced. If your teeth are crowded, missing or significantly misaligned, it may alter your pronunciation and make some sounds less precise. Read more about voice care for performing artists.

For singers, this can affect diction, making lyrics harder for listeners to understand. The position of your teeth and jaw can also influence the amount of space inside the mouth, which affects resonance and tone. 

While the vocal cords produce the sound itself, the teeth, tongue, lips and jaw act as resonators that shape and project the voice. For most people the effect is subtle, but professional singers and performers may notice improvements in clarity and vocal control once significant bite or alignment problems have been corrected.

Can jaw growth cause speech problems?

Yes, jaw development can influence speech. If the upper or lower jaw grows differently than expected, it can affect how the tongue, lips and teeth work together.

Children whose lower jaw is positioned much further forwards or backwards may develop compensatory speech patterns to make certain sounds. These patterns can continue into adulthood if the underlying jaw position is not corrected.

Jaw development can also affect the size of the airway and the amount of space available for the tongue. In some cases, restricted tongue movement or poor tongue posture can contribute to unclear speech.

Not everyone with a jaw difference develops speech problems, but the risk is higher when the bite significantly affects tongue placement.

Can orthodontic treatment improve speech?

Orthodontic treatment can improve speech if bite problems are contributing to unclear pronunciation. Braces or clear aligners gradually move the teeth into better positions, allowing the tongue and lips to make more accurate contact during speech.

It is important to remember that speech habits developed over many years do not always change immediately after orthodontic treatment. Some people also benefit from speech and language therapy to learn new tongue positions and improve pronunciation once the teeth have been corrected.

During the first few days after having braces fitted, some people notice temporary changes to their speech while they adjust. This usually settles as they become used to the appliance.

When should you seek professional advice?

If speech problems persist beyond early childhood, or if they develop alongside obvious bite or jaw concerns, it is worth seeking professional advice. A dentist can assess your teeth and bite, while an orthodontist can determine whether jaw or tooth alignment is contributing to the problem.

A speech and language therapist can assess how speech sounds are produced and provide exercises to improve clarity. When several professionals work together, it is often easier to identify the exact cause and choose the most appropriate treatment.

Early assessment is especially important for children, as speech development is still progressing and treatment may be more effective before the jaw has fully developed.

Is there anything else you should know?

Speech is influenced by many factors, including hearing, muscle coordination, tongue movement and brain development, so teeth and jaw position are only one part of the picture. However, they can play a significant role in how clearly sounds are produced.

If you or your child has ongoing speech difficulties alongside crooked teeth, an unusual bite or jaw concerns, it is worth arranging an assessment. Identifying the cause early can help improve communication, confidence and overall oral health, and in many cases, a combination of orthodontic treatment and speech therapy provides the best long-term outcome.