Child Cannot Say the TH Sound
The short answer
The TH sound is one of the last speech sounds to develop, typically not mastered until age 6 to 8. Substituting F for TH (saying "fumb" for "thumb") or D for TH (saying "dis" for "this") is extremely common and completely normal in young children. Speech therapy is only needed if TH errors persist past age 7.
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By Age
What to expect by age
TH sounds are not expected at all. Most children substitute F, D, or T for TH. This is completely normal and no cause for concern.
TH substitutions remain normal. Children typically use F for voiceless TH (as in "thumb") and D for voiced TH (as in "this"). These substitutions do not affect intelligibility and are age-appropriate.
Some children begin producing TH sounds correctly in some words, but many still substitute. Both are normal. TH is not a priority for speech therapy at this age.
TH production is emerging for many children. Some research suggests TH may not be fully mastered until age 7 or even 8. If your child can produce other sounds well but still struggles with TH, this is typical.
TH should be mastered by age 7 to 8. If your child still cannot produce TH sounds at this age, speech therapy can help. TH is usually straightforward to teach once a child is developmentally ready.
What Should You Do?
When to take action
- Your child is under 6 and says F instead of TH or D instead of TH
- Your child can produce TH in some words but not others
- Your child's only speech error is TH substitution while all other sounds are correct
- Your child is aware of the TH sound and trying to produce it but has not yet mastered it
- Your child is over 7 and still consistently substitutes other sounds for TH
- Your child has TH errors combined with multiple other speech sound errors
- Your child's TH substitution is part of a broader pattern of speech delay
- Your child previously produced TH correctly and has lost this ability
- Your child is school-age and multiple speech errors including TH are significantly affecting communication
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
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