How to Teach the TH Sound: A Parent’s Guide

✓ Reviewed against ASHA Practice Portal, ASHA developmental milestonesEvidence level ALast reviewed July 1, 2026Published July 1, 2026

To teach the TH sound, have your child rest the tongue tip lightly between the front teeth and blow air out: voiceless TH (as in “think”) is air only, while voiced TH (as in “this”) adds voice. TH is a late sound — voiced TH is usually mastered around age 5 and voiceless TH around age 6.

How the TH sound is made

TH is an “interdental” sound — the tongue tip sits lightly between the top and bottom front teeth while air flows out over it. That visible tongue position is actually good news for parents: unlike hidden sounds such as “k” or “g,” you can see and model TH in a mirror.¹

English has two TH sounds spelled the same way. Both use the same tongue-between-teeth placement; the only difference is whether the voice is turned on. Getting the placement right is the first step for either version.¹

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The “polite tongue” cue

Kids respond well to a playful cue like “let your tongue peek out to say hello, then blow.” A tiny bit of tongue showing between the teeth is exactly what you want.

Voiced vs. voiceless TH

The two TH sounds are made in the same place but feel different in the throat. Voiceless TH is just air. Voiced TH adds voice, so a hand on the throat feels a buzz.¹

The two TH sounds in English.
Type	Voice?	Example words
Voiceless TH	Air only, no buzz	think, bath, tooth, math, mouth
Voiced TH	Voice on, throat buzzes	this, that, mother, feather, smooth

The two TH sounds in English.

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Feel the difference

Have your child rest a hand on their throat. “Think” stays quiet; “this” makes the throat hum. Same tongue, different engine.

When children master the TH sound

TH is genuinely hard, and it comes in late. A large review of U.S. children found that by the age at which about 90% of children produce a sound correctly, voiced TH (as in “this”) lands around age 5 and voiceless TH (as in “think”) around age 6 — among the very last consonants to develop, alongside “r.”¹²

This is why milestone guidance lists “th,” “r,” and “l” as sounds children may still mispronounce well into the preschool years. A 4- or 5-year-old saying “fumb” for “thumb” is usually developing normally, not delayed.^3,4,8

Age 5–6when most children master voiced then voiceless TH.¹²

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Late is normal

Because TH develops so late, most young children who miss it are simply on schedule. Intelligibility — how well people understand your child overall — matters more than any single sound.

Common TH error patterns

Because TH is late and tricky, children lean on easier sounds that look or feel similar. Three swaps show up the most.¹

TH → F: “fumb” for “thumb,” “baf” for “bath.” F and voiceless TH look and sound alike, so this is the most common substitution.
TH → D: “dis” for “this,” “dat” for “that.” This is “stopping” — a stop sound like D replaces the continuous airflow of voiced TH.
TH → S: “sink” for “think,” “mouse” for “mouth,” often heard alongside a lisp when the tongue sits just behind rather than between the teeth.

A single swap on TH alone is usually an articulation quirk. When the same pattern (like stopping) affects a whole group of sounds — as ASHA describes for phonological patterns — it is more likely a phonological pattern worth an evaluation.^1,2

How to teach the TH sound: step by step

Work at a mirror in short, upbeat bursts. Build the sound up in stages, and only move on when the step before it feels easy.

1Show the placement. Stick your own tongue tip lightly between your front teeth so your child can copy the “tongue peeking out” look.
2Add air. Keep the tongue there and blow gently — that soft, breathy stream is voiceless TH (as in “think”).
3Add voice. Same tongue, now turn the voice on so the throat buzzes — that is voiced TH (as in “this”).
4Say it in words. Start with easy targets like “thumb,” “bath,” or “this,” then build to longer words and short phrases.
5Use it in play. Fold TH words into games, books, and everyday talk so practice feels natural, not like a drill.

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Skip the tongue push-ups

Non-speech mouth exercises like blowing or tongue wiggles do not teach speech sounds. The fastest path is practicing the actual sound in real words.

Free TH Sound Practice

Practice the TH sound and get instant, private AI feedback.

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TH practice words by position

Practice TH in every position of a word — the beginning, middle, and end — since a child may nail it in one spot but not another. Start with whichever list is easiest and build from there.

TH practice words by position (mix of voiceless and voiced TH).
Position	Words
Beginning	thumb, think, three, thank, this, that, they
Middle	bathtub, birthday, feather, mother, nothing, toothbrush
End	bath, tooth, mouth, math, with, smooth, breathe
Short phrases	thumbs up, three things, bath time, brush your teeth

TH practice words by position (mix of voiceless and voiced TH).

When TH is steady in single words, try minimal pairs that put TH right next to its usual swap — “thin vs. fin,” “thick vs. sick,” “thumb vs. dumb.” Hearing and feeling the contrast helps a child lock in the correct sound.¹

Home practice tips

Short and frequent beats long and rare. A few minutes of TH practice most days, woven into routines you already have, works better than one long session.⁶

Use a mirror so your child can watch the tongue peek between the teeth.
Model the correct word warmly instead of asking your child to “say it again” — “Yes, your thumb!”
Pick a few TH target words for the week and sprinkle them into books, snacks, and play.
Keep it light. Praise good tries, and stop before it turns into a battle.

SpeechStep turns this into a simple daily habit: your child practices the exact TH words they are working on and gets instant, private feedback on whether the sound was right — a helpful bridge between home practice and professional therapy.

When to see a speech-language pathologist

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When to get an evaluation

Because TH develops so late, brief errors are usually fine. Consider an evaluation if TH errors persist past about age 7, your child is hard to understand, the same swap affects many sounds, or home practice is not helping.

A certified speech-language pathologist (SLP) can assess how the sound is being produced, check whether the pattern is articulation or phonological, and target it directly — in person or by teletherapy, which is effective for many children.^10,9

You often do not need to wait for a referral. Your local school district can evaluate a child age 3 and older, and you can also find a certified SLP privately through ASHA’s directory.^11,7

Frequently asked questions

How do you make the TH sound?＋

Rest the tongue tip lightly between the top and bottom front teeth and gently push air out over the tongue. Voiceless TH (as in “think”) uses air only; voiced TH (as in “this”) adds voice, so you feel a buzz in the throat. Because you can see the tongue between the teeth, TH is one of the easier sounds to model in a mirror.

When should a child be able to say the TH sound?＋

TH is one of the last English sounds to develop. In reviews of U.S. children, voiced TH (as in “this”) is typically mastered around age 5 and voiceless TH (as in “think”) around age 6. A 4- or 5-year-old who still says “fumb” for “thumb” is often right on schedule.

Why does my child say “f” or “d” for TH?＋

These are the two most common TH swaps. TH→F (“fumb” for “thumb”) happens because F and voiceless TH sound and look similar. TH→D (“dis” for “this”) is called stopping — a stop sound like D replaces the airflow of TH. Both are common in young children and usually fade as TH develops.

How do I teach the TH sound at home?＋

Sit at a mirror and show your child the tongue tip peeking between the front teeth while you blow air. Have them copy the “tongue between teeth” look first, then add air, then a word. Start with easy words like “thumb” or “bath,” practice in short bursts, and keep it playful. Non-speech tongue exercises are not needed — practice the sound itself.

When should I see a speech therapist about the TH sound?＋

Consider an evaluation if TH errors continue past about age 7, if your child is hard for others to understand, if the same swap affects many other sounds, or if practice at home is not helping. A certified speech-language pathologist can assess the pattern and target it directly.