Child Cannot Say the TH Sound
Medically reviewed by Dr. Emily Torres, PhD, CCC-SLP · Pediatric Speech-Language Pathologist
Content reviewed against published ASHA, AAP, NIH guidelines
Last reviewed:
Speech and communication milestones vary widely, and worries about child cannot say the th sound, here is what you need to know.
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.
Key takeaways
- 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.
- Usually normal when: Your child is under 6 and says F instead of TH or D instead of TH
- Call your doctor if: Your child previously produced TH correctly and has lost this ability
- Varies by age — see the age-by-age breakdown below
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What Parents Should Know
According to ASHA, AAP, NIH guidelines, 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. At 2-3 years, 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. It is generally considered normal when your child is under 6 and says F instead of TH or D instead of TH. However, you should contact your pediatrician promptly if your child previously produced TH correctly and has lost this ability.
Normal vs. Concerning
By Age
What to expect by age
2-3 years
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.
3-4 years
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.
4-5 years
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.
5-6 years
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.
6-8 years
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 to Tell Your Pediatrician
- Describe when you first noticed child cannot say the th sound and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your child is over 7 and still consistently substitutes other sounds for TH.
- Mention if your child has TH errors combined with multiple other speech sound errors.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
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
What You Can Do at Home
- Keep track of when you notice child cannot say the th sound — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that your child is under 6 and says F instead of TH or D instead of TH — this is generally within the range of normal.
- At 2-3 years, focus on observation rather than intervention unless your pediatrician advises otherwise.
- Talk, read, and sing to your baby frequently. Narrate daily activities to build language exposure.
- While monitoring at home, seek immediate care if your child previously produced TH correctly and has lost this ability.
Related Conditions
My Child's Speech Is Hard to Understand (Articulation)
Speech clarity improves gradually: strangers typically understand about 50% of a 2-year-old's speech, 75% at age 3, and nearly 100% by age 4. If you can understand your child but others can't, that's often normal - you're an expert in your child's speech patterns. But if even you struggle to understand your child by age 2-2.5, or if strangers can't understand most of what your 3-year-old says, a speech evaluation is a good idea.
Toddler Has Multiple Speech Sound Errors
A speech sound disorder involves difficulty producing speech sounds correctly, making a child harder to understand than expected for their age. While individual sound errors are common in toddlers, having many sound errors that significantly reduce intelligibility may indicate a speech sound disorder that benefits from speech therapy. Early evaluation and treatment lead to the best outcomes.
My Child Has Difficulty with Consonant Sounds
Consonant sounds develop in a predictable order, and no child masters them all at once. Early consonants (m, b, p, d, n) typically emerge by age 2, while later consonants (r, l, s, sh, th) may not be mastered until age 6-7. If your child is consistently only using vowels with no consonants past 12 months, that's worth evaluating. But if they have some consonants and are missing the trickier ones, they're likely right on track.
Related Resources
Milestone Checklists by Age
Track your baby's developmental milestones from birth to 5 years with age-specific checklists.
Month-by-Month Development
Detailed monthly development guides from birth through 24 months.
When to Call the Doctor
General guide on when to call the pediatrician, visit urgent care, or go to the ER.
Frequently asked questions
Is child cannot say the th sound normal?
When should I call the doctor about child cannot say the th sound?
When is child cannot say the th sound normal?
What causes child cannot say the th sound?
What should I mention to my pediatrician about child cannot say the th sound?
Is child cannot say the th sound normal at 2-3 years?
Is child cannot say the th sound normal at 3-4 years?
Should I go to the ER for child cannot say the th sound?
Does child cannot say the th sound go away on its own?
References
- [1]American Speech-Language-Hearing Association. Speech Sound Disorders: Articulation and Phonology. ASHA
- [2]American Academy of Pediatrics. Speech and Language Development. HealthyChildren.org. AAP
- [3]National Institute on Deafness and Other Communication Disorders. Speech and Language Developmental Milestones. NIH
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Child Cannot Say the TH Sound.
Things to mention
- Describe when you first noticed child cannot say the th sound and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your child is over 7 and still consistently substitutes other sounds for TH.
- Mention if your child has TH errors combined with multiple other speech sound errors.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- 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
Urgent signs to report immediately
- 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
My notes
From ismybabyalright.com — free, evidence-based baby health guides
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members
Related Resources
Bottom line
Most cases of child cannot say the th sound are normal. Talk to your pediatrician if your child previously produced th correctly and has lost this ability.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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Related Speech Concerns
My Child's Speech Is Hard to Understand (Articulation)
Speech clarity improves gradually: strangers typically understand about 50% of a 2-year-old's speech, 75% at age 3, and nearly 100% by age 4. If you can understand your child but others can't, that's often normal - you're an expert in your child's speech patterns. But if even you struggle to understand your child by age 2-2.5, or if strangers can't understand most of what your 3-year-old says, a speech evaluation is a good idea.
Toddler Has Multiple Speech Sound Errors
A speech sound disorder involves difficulty producing speech sounds correctly, making a child harder to understand than expected for their age. While individual sound errors are common in toddlers, having many sound errors that significantly reduce intelligibility may indicate a speech sound disorder that benefits from speech therapy. Early evaluation and treatment lead to the best outcomes.
My Child Has Difficulty with Consonant Sounds
Consonant sounds develop in a predictable order, and no child masters them all at once. Early consonants (m, b, p, d, n) typically emerge by age 2, while later consonants (r, l, s, sh, th) may not be mastered until age 6-7. If your child is consistently only using vowels with no consonants past 12 months, that's worth evaluating. But if they have some consonants and are missing the trickier ones, they're likely right on track.
Accent vs Speech Disorder in Bilingual Toddlers
When toddlers grow up hearing more than one language, they naturally blend sounds, patterns, and accents from both languages. This is normal and healthy, not a speech disorder. A bilingual child may pronounce some sounds differently than monolingual peers because they are learning the sound systems of two languages simultaneously. True speech disorders affect both languages equally, while accent influence appears only in specific sounds borrowed from one language to another.
Ear Fluid Affecting Baby's Speech Development
Chronic or recurrent middle ear fluid (otitis media with effusion) can temporarily reduce hearing by 15 to 40 decibels, which is like hearing through water. During critical periods of language learning, this muffled hearing can impact speech and language development. If your baby has frequent ear infections or persistent fluid, discuss the potential speech impact with your pediatrician.
Will Ear Tubes Help My Child's Speech?
Ear tubes (tympanostomy tubes) can restore normal hearing by draining persistent fluid from the middle ear. Many children show speech and language improvement within weeks to months after tube placement, particularly if hearing loss from fluid was contributing to their speech delay. However, ear tubes alone may not resolve all speech delays, and some children benefit from speech therapy alongside tube placement.