The two TH sounds: /θ/ and /ð/

The letters th usually stand for one of two sounds: /θ/ in think and /ð/ in this. Your tongue uses the same position; your voice makes the difference.

These examples follow General American English. Other accents can differ.

Start with the tongue, then add your voice

  1. Rest the tip of your tongue lightly against your upper front teeth, or let it show just a little between your teeth. Do not bite it.
  2. Let air flow through the small gap. Keep it flowing rather than stopping and releasing it as you would for /t/ or /d/.
  3. For /θ/, use air without a voice buzz. For /ð/, keep the position and add voice. Touch your throat gently to compare them.

Try a held /θ/, then a held /ð/. Practise the position slowly before putting the sound into words.

Words to compare

SoundExamplesWhat to notice
/θ/ — voice offthink /θɪŋk/, three /θriː/, teeth /tiːθ/Air continues through the gap.
/ð/ — voice onthis /ðɪs/, that /ðæt/, mother /ˈmʌðɚ/Feel the voice buzz as well as the airflow.

Say teeth, then teethe /tiːð/ (what a baby does when teeth grow). The last sound changes from /θ/ to /ð/.

Spelling does not tell you everything: think and this start with the same letters but different sounds. Thomas starts with /t/. Learn a word together with its pronunciation.

Three common substitutions

  • Think → sink: for /s/, the tongue stays farther back. Bring the tip forward for /θ/.
  • Thin → tin or this → dis: do not close the air passage completely. Keep the air moving.
  • Three → free: /f/ uses the upper teeth and lower lip. TH uses the tongue and teeth.

Try it, then check

Say three thin things, then this, that, those. Which group uses /θ/? Which uses /ð/?

Show the answers and reasons
Three thin things: /?/.
These TH sounds are voiceless: keep light tongue contact without vibrating your vocal folds. Read the guide
This, that, those: /?/.
These TH sounds are voiced: use the same light tongue contact with vocal-fold vibration. Read the guide

Open the sound chart and choose /θ/ and /ð/ to hear each in example words. The minimal-pairs game practises /θ/ against /s/ in think/sink; it does not test /θ/ against /ð/.

Hear TH in the sound chart Practise think and sink

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