SpeakMetry
Start free

Pronunciation · Minimal pairs · low functional load

/θ/ vs /s/ — think vs sink

In short

The dental /θ/ and the sharp /s/ separate think/sink, thick/sick and mouth/mouse. Research ranks this a low-functional-load contrast — it rarely blocks understanding — but it is one of the most NOTICED features of a non-native accent. This contrast carries a LOW functional load — it separates few word pairs, so while the substitution is noticeable, it rarely blocks understanding. Treat it as polish, not priority.

How to hear (and make) the difference

The tongue tip must be visibly between your teeth for /θ/ — check in a mirror. /s/ keeps it hidden behind the teeth. Slow, exaggerated practice rewires the habit fastest.

Most challenging for French, Japanese, Mandarin, Vietnamese, Turkish speakers.

8 minimal pairs with audio

Play each side and copy it. Then read the pairs aloud — can a listener tell which word you said?

  • think/θɪŋk/
    sink/sɪŋk/
  • thick/θɪk/
    sick/sɪk/
  • thing/θɪŋ/
    sing/sɪŋ/
  • mouth/maʊθ/
    mouse/maʊs/
  • path/pɑːθ/
    pass/pɑːs/
  • thumb/θʌm/
    sum/sʌm/
  • worth/wɜːθ/
    worse/wɜːs/
  • faith/feɪθ/
    face/feɪs/

Test your ear

Perception comes before production: if you can't hear the contrast, you can't say it reliably. Free, unlimited, different voices each round.

Listening drill

/θ/ vs /s/ — think vs sink

1/8

The tongue tip must be visibly between your teeth for /θ/ — check in a mirror. /s/ keeps it hidden behind the teeth. Slow, exaggerated practice rewires the habit fastest.

The contrast in sentences

Same sentence frame, different word — say both versions and make them unmistakably different.

  • I think it's broken.

    I sink it's broken.

  • He looked thick.

    He looked sick.

Keep exploring

Frequently asked questions

What is the difference between think and sink?
think /θɪŋk/ uses the /θ/ sound while sink /sɪŋk/ uses /s/. The tongue tip must be visibly between your teeth for /θ/ — check in a mirror. /s/ keeps it hidden behind the teeth. Slow, exaggerated practice rewires the habit fastest.
What are minimal pairs and why practise them?
Minimal pairs are word pairs that differ by exactly one sound (ship/sheep). Practising them trains your ear and mouth on the single difference that separates the words — perception research (high variability phonetic training) shows this transfers to real speaking.
Which learners find the /θ/ vs /s/ contrast hardest?
It is most challenging for French, Japanese, Mandarin, Vietnamese, Turkish speakers, whose first languages don't separate these two sounds.
Do these pairs matter for IELTS Speaking?
They help. IELTS scores intelligibility, so contrasts that change word meaning matter most — this one is worth practising once the high-priority vowel contrasts are stable.

Next step

Get scored saying these pairs

SpeakMetry's Pronunciation Coach listens to you say each pair and tells you whether the contrast survived — plus which sound to fix and how.

Try the speaking drill free