Speaking of Thumb Sucking - how thumb sucking can affect speech.


Thumb sucking and finger sucking are common habits among young children. Because of this, many parents may not realize the potential effects that sucking habits can have on their child's speech development. While thumb sucking may seem harmless, prolonged, and frequent thumb sucking can lead to a variety of speech-related problems, including articulation and pronunciation difficulties.

In this blog, we will discuss how thumb sucking affects speech, the age at which thumb sucking may become problematic, and what parents can do to help their child break the habit.


How Thumb Sucking Affects Speech

Thumb sucking can affect speech in several ways. The most common way is through the deformation of the palate, which is the roof of the mouth. This deformation of the palate can cause a high and narrow arch to the roof of the mouth. This reduces the space in the oral cavity, making it difficult for the tongue to move freely during speech and sound production. Consequently, children may struggle with the correct placement of their tongue, leading to a variety of speech sound errors.

For example, children who suck their thumbs may have difficulty pronouncing sounds that require the tongue to be at the front of the mouth, such as "t", "d", "l", and "n". This is because the tongue is pushed backward in the mouth, making it difficult to produce these sounds correctly. They may also struggle with sounds that require the tongue to move quickly, such as "s" and "z".

Another way thumb sucking can affect speech is through the positioning of the teeth. Frequent and prolonged thumb sucking can cause the front teeth to push forward, which can lead to an open bite. An open bite occurs when the front teeth do not meet when the child bites down. This can make it difficult for the tongue to make certain sounds that require contact between the upper and lower teeth, such as "f" and "v". An open bite can also cause air leakage during speech production, which can affect the clarity of speech.

In addition to mispronunciation and an open bite, thumb sucking can also affect the rhythm and flow of speech. Children who suck their thumbs may have a slower rate of speech due to the positioning of their tongue and palate. This can make it difficult for them to keep up with their peers during conversations and affect their overall communication skills.


The Age at Which Thumb Sucking May Become Problematic

Most children stop sucking their thumbs by the age of 4, and it is generally not considered a problem before this age. However, if a child continues to suck their thumb past the age of 4, it may become problematic for speech development.

The reason for this is that the permanent teeth start to come in at around the age of 6. If a child is still sucking their thumb at this age, it can cause the permanent teeth to shift and grow in incorrectly, which can affect speech development. 

What Parents Can Do to Help Their Child Break the Habit

Breaking the habit of thumb sucking can be challenging for both the child and the parents. Here are some tips for parents to help their child break the habit:

  • Praise and Reward

Praise and reward your child for not sucking their thumb. Positive reinforcement is an effective way to encourage good behaviour.

  • Provide Distractions

Provide your child with distractions to keep their hands busy. This can include toys, games, or other activities that they enjoy.

  • Use a Thumb Guard

A thumb guard can be used to cover the thumb. It forms both a physical barrier to prevent your child from gaining suction when attempting to suck their thumb, and it provides a visual reminder not to put their thumb into their mouth.

  • Talk to Your Child

Talk to your child about the habit and explain why it is important to break it. Use age-appropriate language to help them understand.

  • Seek Professional Help

If your child is having difficulty breaking the habit, or you are concerned about their speech, consider seeking professional help from a speech therapist or paediatric dentist.


Thumb sucking can affect speech development. It can cause the palate to become narrow and high, affect the positioning of the teeth and interfering with the correct placement of the tongue against the teeth. While thumb sucking is generally not considered a problem before the age of 4, it can become problematic if the habit persists past this age.

Parents can help their child break the habit of thumb sucking by using positive reinforcement, providing distractions, using a thumb guard, talking to their child about the habit, and seeking professional help if necessary.

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