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
- packpækbackbæk
- pearpeəbearbeə
- pigpɪɡbigbɪɡ
- pathpɑːθbathbɑːθ
- capkæpcabkæb
- roperəʊproberəʊb
- praypreɪbraybreɪ
Test your ear
Listening drill
/p/ vs /b/: pack vs back
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
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'.
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.