Labioalveolar

From KneeQuickie

Labioalveolar consonants are articulated by raising the lower lip, rather than the tongue, towards the alveolar ridge.

The IPA considers labioalveolars to be characteristic of "disordered speech"; they are not phonemic in any natlangs. There is no way to represent labioalveolar consonants in X-Sampa; in Z-Sampa they are written by adding the alveolar diacritic _a\ to the corresponding labiodental or bilabial consonant: for example, /F_a\/ or /p_a\/.