The initials b, p, m and f involve the lips.

A listening contrast#

Compare b with p using the reference audio or a teacher. Aspiration—the release of air—is central to this contrast. Do not simply read the letters with English consonant values.

Suggested practice#

Record yourself saying bā and pā, then compare the release of air. Next practise mǎ and fǎ as separate syllables. This is an exercise, not a test that can certify pronunciation from text alone.

Reference#

Pronunciation reference. The practice instructions here are newly written. Recordings, charts and illustrations from the reference are not reproduced.