Sound Safari
Stopping
/th/ → /t/
Typically resolves on its own by around age 4; worth a check-in if it persists.
What helps →
Show the tongue position in a mirror — /t/ is hidden behind the teeth, /th/ pokes between them. Practice slowly with a mirror.
Speech Sound Guide
The Voiceless TH Sound: Norms, Challenges & Word Lists
The /th/ sound is one of the later sounds children master — typically by age 7. This guide covers when /th/ develops, what typically goes wrong, simple ways to practice it, and over 90 /th/ words organized by position.
When should a child say /th/?
Developmental norms — when the /th/ sound typically emerges and is mastered.
Late-developing
7
Age of 90% mastery
years;months notation
50% mastery
Age 4
90% mastery
Age 7
Manner
fricative Fricatives are made by forcing air through a narrow gap — they hiss or buzz (like /s/, /f/, /sh/).
Voicing
Voiceless Voiceless sounds don't vibrate the vocal cords — just air, no buzz.
Where /th/ falls on the speech-sound timeline
2 yrs4 yrs6 yrs8 yrs
Source: McLeod & Crowe (2018); Crowe & McLeod (2020), AJSLP.
A child still substituting or distorting /th/ after age 7 is a good candidate for a speech-language evaluation — earlier if they're hard to understand or frustrated.
Find out where /th/ stands — in 5 minutes
Sound Safari's 24-sound screener checks against the McLeod & Crowe norms above.
Common challenges with /th/
What typically goes wrong — and whether it's age-appropriate.
How to practice the /th/ sound
Practical starting points for parents and SLPs. Always follow your SLP's plan if your child is in therapy.
- 1 Tongue between the teeth. /th/ is made with the tongue gently between the top and bottom teeth — not biting, just resting. Have your child practice the position in a mirror before adding any sound.
- 2 Blow gently. /th/ is a quiet fricative — just air passing over the tongue. No voice, no buzz. Have your child blow softly while the tongue is between the teeth.
- 3 Feel the air on a finger. Hold a finger just in front of your child's mouth. They should feel a faint stream of air with each /th/ — confirms the sound is air, not a /t/ stop.
- 4 Contrast pairs — /th/ vs. /f/ and /s/. /th/ is often replaced with /f/ (think → fink) or /s/ (think → sink). Use pairs like thin/fin, thank/sank to train the ear and the mouth.
- 5 Start with words that show the tongue. Use a mirror and start with words that begin with /th/ (think, thumb, three) so the tongue position is visible the whole time.
📖 For the full step-by-step therapy progression, see our complete
Voiceless TH Sound Therapy Guide →
/th/ word lists by position over 90 words
Every word from the Sound Safari practice library. The /th/ in each word is bolded.
Initial — /th/ at the start of the word (30)
-
thumb thum -
think think -
three three -
throw throh -
thick thik -
thin thin -
thing thing -
thirst therst -
thirteen ther-teen -
thirty ther-tee -
thorn thorn -
thought thawt -
thousand thow-zand -
thread thred -
threat thret -
throne throhn -
through throo -
thud thud -
thunder thun-der -
thump thump -
Thursday therz-day -
thankful thank-ful -
therapy ther-uh-pee -
thermal ther-mal -
thermometer ther-mom-eh-ter -
thicket thik-et -
thimble thim-bul -
thrill thril -
thrive thryv -
throat throht
Medial — /th/ in the middle of the word (30)
-
birthday burth-day -
bathtub bath-tub -
toothbrush tooth-brush -
anything en-ee-thing -
athlete ath-leet -
bathroom bath-room -
bathrobe bath-rohb -
cathedral kuh-thee-drul -
earthquake erth-kwayk -
everything ev-ree-thing -
faithfully fayth-ful-ee -
footpath foot-path -
healthful helth-ful -
marathon mar-uh-thon -
mouthful mowth-ful -
nothing nuth-ing -
pathway path-way -
python py-thon -
something sum-thing -
toothache tooth-ayk -
toothpaste tooth-payst -
toothpick tooth-pik -
truthful trooth-ful -
worthwhile werth-wyl -
youthful yooth-ful -
athena uh-thee-nuh -
ether ee-ther -
ethic eth-ik -
method meth-ud -
methane meth-ayn
Final — /th/ at the end of the word (30)
-
bath bath -
tooth tooth -
math math -
path path -
birth berth -
booth booth -
breath breth -
broth broth -
beneath bee-neeth -
cloth kloth -
depth depth -
earth erth -
faith fayth -
filth filth -
forth forth -
froth froth -
growth grohth -
health helth -
length length -
mammoth mam-uth -
month munth -
moth moth -
mouth mowth -
myth mith -
north north -
south sowth -
strength strength -
truth trooth -
width width -
worth werth
Minimal pairs for /th/
Minimal pairs differ by a single sound — the heart of phonological therapy. Tap a card to hear it, or tap “vs” to hear a pair back-to-back.
More /th/ minimal pairs — tap a contrast to explore
/th/ at the start · 8
- than can
- that cat
- thorn corn
- through crew
- throw crow
- they key
- thick kick
- thing king
/th/ at the end · 4
- bath back
- forth fork
- fourth fork
- path pack
IEP goals for /th/
A starting point for SLPs writing articulation goals — across the six therapy levels.
Goal progression — tap a level to see the goal
Sample goal — word level
"Given a verbal model, [student] will produce /th/ in the initial position of words with 80% accuracy across 3 consecutive sessions."
Track /th/ progress automatically
Sound Safari logs every trial against your goals and writes the SOAP note for you.
/th/ sound — frequently asked questions
At what age should my child say the /th/ sound? +
Most children produce /th/ correctly by age 7. About half can do it by age 4. /th/ is one of the latest English sounds to develop.
Is it normal for my child to say "f" or "s" for "th"? +
Yes — substituting /f/ ("fink" for "think") or /s/ ("sink") for /th/ is developmentally typical up to about age 6. If it persists past age 7, it's worth a check-in.
Why is the /th/ sound so hard? +
/th/ requires the tongue to sit between the teeth — a position most other English sounds avoid. It also has very little airflow, so the sound is quiet and easy to confuse with /f/ or /s/.
How can I help my child practice /th/ at home? +
Use a mirror so the child can see the tongue between the teeth, practice blowing gently, and use contrast pairs (thin/fin) to train the ear. See "How to practice" above.
When should we see a speech therapist about /th/? +
If /th/ is still being replaced with /f/, /s/, or /t/ after age 7, or sooner if your child is frustrated or hard to understand.
Can older children and adults still correct /th/? +
Yes. /th/ is treatable at any age. The tongue position is visible and easy to demonstrate, so most older learners make steady progress.
Related sounds
Sounds that pair, contrast, or are commonly confused with /th/.
