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Pronunciation · Minimal pairs · high functional load

/p/ vs /b/ — pack vs back

In short

The voiceless /p/ and voiced /b/ separate a huge number of words — pear/bear, pig/big, cap/cab. English relies on the puff of air (aspiration) at the start of /p/ to keep them apart. This contrast carries a HIGH functional load — confusing these two sounds frequently turns one real word into another, which is what actually damages intelligibility (Munro & Derwing 2006 found one high-load error hurts comprehensibility more than three low-load errors combined).

How to hear (and make) the difference

Hold a tissue in front of your lips: it should jump on 'pack' and stay still on 'back'. At word ends, keep /b/ gently voiced — 'cab' must not become 'cap'.

Most challenging for Arabic, Korean, Indonesian, Farsi speakers.

7 minimal pairs with audio

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

  • pack/pæk/
    back/bæk/
  • pear/peə/
    bear/beə/
  • pig/pɪɡ/
    big/bɪɡ/
  • path/pɑːθ/
    bath/bɑːθ/
  • cap/kæp/
    cab/kæb/
  • rope/rəʊp/
    robe/rəʊb/
  • pray/preɪ/
    bray/breɪ/

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

/p/ vs /b/ — pack vs back

1/8

Hold a tissue in front of your lips: it should jump on 'pack' and stay still on 'back'. At word ends, keep /b/ gently voiced — 'cab' must not become 'cap'.

The contrast in sentences

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

  • Take the path on the left.

    Take the bath on the left.

  • The cap is waiting outside.

    The cab is waiting outside.

Keep exploring

Frequently asked questions

What is the difference between pack and back?
pack /pæk/ uses the /p/ sound while back /bæk/ uses /b/. Hold a tissue in front of your lips: it should jump on 'pack' and stay still on 'back'. At word ends, keep /b/ gently voiced — 'cab' must not become 'cap'.
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 /p/ vs /b/ contrast hardest?
It is most challenging for Arabic, Korean, Indonesian, Farsi speakers, whose first languages don't separate these two sounds.
Do these pairs matter for IELTS Speaking?
Yes — high-functional-load contrasts like this one are exactly what the examiner hears as 'mispronunciation reduces clarity'. Mastering them is one of the fastest routes from Band 6 to Band 7 pronunciation.

Next step

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