Which sounds are produced by contact between the maxillary incisors and the wet/dry line of the lower lip?

Which sounds are produced by contact between the maxillary incisors and the wet/dry line of the lower lip?

• A. Bilabial sounds = b, p, m
• B. Fricative or labiodental sounds = f, v, ph
• C. Guttural sounds = g, k
• D. Sibilant or linguoalveolar sounds = s, z, sh, ch, j

Answer: (B)

Labiodental sounds come from the lower lip touching the upper front teeth, creating a constriction at the lips-teeth border, specifically at the wet/dry line. That setup makes the airflow turbulent as it passes through the small gap, producing frication—so these sounds are fricatives. The classic examples are f and v, which are produced this way. In some descriptions the sound may be represented with symbols like ph as well, but the essential idea is the same: contact between the lower lip and the upper incisors with a fricative airstream. The other groups involve different places or manners of articulation—bilabial uses both lips, guttural sounds come from the back of the mouth, and sibilants/linguoalveolars involve the tongue against the teeth or alveolar ridge—so they do not match the lip-teeth contact pattern described.

Labiodental sounds come from the lower lip touching the upper front teeth, creating a constriction at the lips-teeth border, specifically at the wet/dry line. That setup makes the airflow turbulent as it passes through the small gap, producing frication—so these sounds are fricatives. The classic examples are f and v, which are produced this way. In some descriptions the sound may be represented with symbols like ph as well, but the essential idea is the same: contact between the lower lip and the upper incisors with a fricative airstream. The other groups involve different places or manners of articulation—bilabial uses both lips, guttural sounds come from the back of the mouth, and sibilants/linguoalveolars involve the tongue against the teeth or alveolar ridge—so they do not match the lip-teeth contact pattern described.