Textbooks call this voiced against voiceless, which is true and useless, because you cannot hear anyone else's vocal cords. What you can hear is a delay.
Same Lips, Different Timing
Both sounds start identically: lips sealed, pressure building behind them. What separates them is what happens in the fraction of a second after they open.
b in bear
The lips open and the vowel starts almost immediately. Your voice is already switched on. There is no gap and no puff — the word begins straight away.
p in pear
The lips open and a puff of breath escapes first, then the vowel arrives a moment later. That small delay of pure air is the real signal, and it is why p feels sharper.
Listen for the Delay, Not the Voicing
Textbooks describe this as voiced against voiceless, which is technically right and practically unhelpful — you cannot hear someone else's vocal cords. What English listeners actually use is timing: how long after the lips open does the vowel begin? On b it is instant. On p there is a breath of hesitation first. Retrain your attention onto that gap rather than onto the consonant itself, and this pair starts separating. The gap is also more robust than voicing on a bad connection, because it survives compression better.
Why the Merge Happens
Korean neutralises the voiced and voiceless distinction in certain positions, and word-initial stops in Korean carry aspiration cues that English does not use the same way. Spanish does something comparable. The result is that these two arrive as one sound rather than as two that are hard to separate. Because the difference English actually relies on is timing, and timing is something you can count, this pair improves faster than most once you know where to point your attention.
The Same Timing Test Elsewhere
- coat / goat
Exactly the same timing story, moved to the back of the mouth.
- fan / pan
Keeps the p and swaps its opponent for a sound that never closes at all.