You are currently viewing The Connection Between Thumb Sucking & Speech Impairments

The Connection Between Thumb Sucking & Speech Impairments

  • Post author:
  • Post category:Blog

Unfortunately for parents of thumb and finger suckers, there is a well-established connection between non-nutritive thumb or finger sucking, and the development of speech impairments. Children with a prolonged and persistent thumb or finger sucking habit, if left untreated, are far more likely to develop speech impairments, as well as a list of other health issues. As a parent, you want to protect your child from the worst possible outcomes.

Is It Normal?

According to the Mayo Clinic, thumb sucking is a very common habit for young children. Since babies have rooting reflexes, it is completely normal and natural for them to express that by sucking on their thumbs or fingers. It makes them feel secure and comfortable. At a certain point, however, consequences emerge from prolonged and vigorous sucking. As they age, babies should ease away from this habit.

How Does Thumb Sucking Affect a Child’s Speech?

The connection between thumb sucking and speech impairments is unfortunately very clear and very impactful. A research study conducted by the U.S. and Chile discovered that children who suck their fingers for more than three years were three times more likely to develop a speech impediment. According to Kids Chatter Speech Pathology, the sucking of one’s thumb can damage one’s ability to swallow and create speech sounds. Interdental lisps are among the most common speech disorders that we see related to thumb and finger sucking.

Interdental lisps involve the tongue extending between the teeth when the child produces an /s/ or /z/ sound. It also affects other sounds that we make with our tongues, including /j/, /ch/, /sh/, /l/, /t/, /n/, and /d/. Since so many sounds can be altered by thumb sucking, it is vital that parents intervene early. If a child develops a severe impediment, it may impact their ability to relate through language or speech.

How Teeth Placement Affects a Child’s Speech

To learn how to correctly use their tongue to create sounds, toddlers and infants should practice oral and motor movements. Thumb sucking, aside from lowering the amount of time spent practicing oral movements, can change an infant’s tongue placement, oral structure, and teeth placement. Unless they are treated by a speech pathologist, babies may develop a lisp from their thumb sucking, an impairment that often carries into adulthood and leads to a great deal of teasing.

How Speech Impairments Impact Language

Children develop language over time by following several stages. The first stage, according to Speech and Occupational Therapy of North Texas, is called “vocal play.” Parents who remember their infant’s cooing while in their beds, perhaps to their favorite toy, are familiar with this kind of behavior. Vocal play has a vital role in a child’s development. It is the very beginning of interaction, and it creates a sort of conversation between a parent and their child. A parent can respond to the child’s sounds with sounds of their own, creating vital eye contact and reassuring the child that the parent cares deeply about what they have to say. Parents will typically use these quasi-conversations as an opportunity to introduce new words to their child. For instance, they may point to a toy truck and say, “truck.” All this creates a very important bond between parent and child, and it develops early language skills.

If a child has something in their mouth, like a thumb, finger, or pacifier, they are not able to create those sounds and therefore are less likely to gain the attention of their parents. Some infants are so dependent on sucking their thumbs and fingers that they cannot engage in vocal play at all. Without those early language skills, babies may grow up to be chastised by or isolated from their crowd of peers.

Other Impacts from Thumb Sucking

Jaw and Teeth

Aside from speech and language, there are other ways that frequent and sustained thumb sucking can damage an infant’s health and appearance in the long term. The motion of thumb sucking disrupts the formation of a child’s jaw and teeth. The impact of thumb and finger sucking could cause malocclusion, or the misalignment of teeth, incorrect tongue movement or placement, or an overbite. All of these problems could lead to poor chewing, a misaligned jaw placement, and the possibility of the professional eye of an orthodontist.


An often overlooked, but no less severe, impact of thumb sucking is its ability to spread germs to a child. Humans constantly pick up germs with their hands. When babies or infants suck on their fingers, they transfer those germs into their mouths.

How To Stop Thumb Sucking

If parents notice a problem, then the best thing to do is start early. For children who have a tendency for putting things in their mouths, parents can build awareness of when the child engages in such behavior by pointing it out and gently discouraging it. Another option is to keep the child occupied with activities, such as reading or playing, to keep them from sucking their thumbs or fingers, or engaging in the oral fixation. If you’re unable to distract the child because their need to suck is so great, you can consider something like a TGuard device, which is worn on the hand, and prevents the child from achieving suction. The child cannot remove the device, ensuring consistent abstinence from the habit, but because the TGuard glove is so soft and flexible, it does not interfere with the child’s daily activities.


After reading this article, you should have a better understanding of the dangers of thumb sucking. Aside from how the habit alters a child’s ability to communicate, it also complicates their ability to interact with the world around them, and leaves them at greater risk of infection from germs or viruses.


Can Thumb Sucking Impact Speech Development?” from Speech and Occupational Therapy of North Texas

Is your child a thumb sucker?” from Kids Chatter Speech Pathology

Prolonged thumb sucking in infants may lead to speech impediments” from (e) Science News

Thumb sucking: Help your child break the habit” from the Mayo Clinic