How to pronounce The /p/ as in PEN /p/ in American English

American English adds a strong puff of air to /p/ when it starts a stressed syllable. Hold a piece of paper in front of your mouth and say pay, pen, or pie and the paper should jump. That extra burst is what makes the /p/ register as a /p/ to American ears. Skip it and the sound thins out, drifting toward /b/, so pie can come across as buy.

Two things separate them: vocal cord vibration and the puff of air. The mouth shape is identical, lips press together to stop the air, then pop open. But /p/ is voiceless, and at the start of a stressed word it releases with a strong puff, like a tiny burst. The /b/ in boy or bat uses your vocal cords, adding a low hum from the throat, with no extra puff. Put two fingers on your throat and say pet: no buzz on the /p/, but you'll feel one on the /b/ in bet. American ears actually lean more on the puff than on the buzzing, so don't skip it.

Most of the time, the lips close to form the /p/ but the air never gets released. In words like stop, cup, or keep, Americans rarely let out that final pop of air. The lips just press together to cut the vowel off short, and the /p/ stays trapped inside the mouth. A hard, explosive /p/ at the end of a sentence isn't wrong, but it sounds stagey next to how people actually talk.