Two sounds close enough to trade places: the “b” of bed and the “p” of pen. Swap one for the other and a different word comes out — this page is how to keep them apart, in both directions.
Keep the voicing on while your lips close for the final consonant, letting the buzz continue into the closure.
“The lips close but the motor must keep running! Buzz INTO the closing, bello — b, not a silent little p!”Nunzio, when he hears it
You cannot hear your own swap. That is the whole problem.
Nunzio records you reading a sentence, scores every sound in it on your phone — nothing is uploaded — and tells you which of these two actually came out. Nunzio — Accent Coach is coming to the App Store and Google Play.