pronouncekit

SOUND CONTRAST

Think vs sink: how to say /θ/ and /s/ clearly

Move your tongue tip forward for /θ/ in think and behind your teeth for /s/ in sink. Practice minimal pairs with seseo and Mandarin-specific guidance.

/θ/ ≠ /s/

Hear the difference in your own voice

Voice settings

What your mouth is doing

Both sounds are voiceless, continuous airflow. The key difference is the tongue. For /θ/, the tongue tip comes forward to the teeth, and the hiss is soft and flat. For /s/, the tongue stays behind the teeth, directing a thin stream that produces a sharper hiss.

Comparing with Mandarin and Spanish

If your language has only /s/ in this space, the tongue position is the new skill. Use a mirror: for /θ/ a small part of the tongue may show, and for /s/ it should not.

Mandarin has s but no /θ/, so think can become sink. Spanish speakers with distinción already have /θ/ in zapato; with seseo, start from /s/ and move the tongue forward.

Build the sound, step by step

  1. Hold /s/ for a moment and notice where your tongue sits.
  2. Without stopping the air, slide the tongue tip forward to the teeth. The hiss will flatten into /θ/.
  3. Read each pair, then say the sentence, keeping the tongue movement small.
I think the ship will sink.

What to watch for

  • Biting the tongue hard blocks the air and creates /t/. Keep contact light.
  • Pushing air harder does not fix /s/ for /θ/. Move the tongue tip instead.

Compare these sounds

Keep practicing

References & editorial notes

PronounceKit wrote this lesson as practical guidance. The references below describe the sounds; the comparisons with other languages are editorial teaching suggestions. It describes common American and British patterns, not every accent, and it has not been independently reviewed by a pronunciation specialist. The mouth model is a simplified teaching aid, not a validated simulation.

Published 3 November 2026