ب، م، و involve the two lips, but their production differs.
ب: the lips close and release, as in بِسْمِ.
م: the lips close with possible accompanying nasal resonance, as in مَالِك.
و: when consonantal rather than a letter of madd, the lips round without the full closure of ba, as in وَلَد.
Keep in mind the contrast between consonantal waw here and long-vowel waw at point 1: the letter's function determines the relevant articulation description.
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Articulation of Letters — All Seventeen Makharij
ب، م، و involve the two lips, but their production differs.
ب: the lips close and release, as in بِسْمِ.
م: the lips close with possible accompanying nasal resonance, as in مَالِك.
و: when consonantal rather than a letter of madd, the lips round without the full closure of ba, as in وَلَد.
Keep in mind the contrast between consonantal waw here and long-vowel waw at point 1: the letter's function determines the relevant articulation description.