Generally precluded are linguolabials, in which the tip of the tongue contacts the posterior side of the upper lip, making them coronals, though sometimes, they behave as labial consonants.
For example, the Spanish consonant written b or v is pronounced, between vowels, as a voiced bilabial approximant.
One exception is Ewe, which has both kinds of fricatives, but the labiodentals are produced with greater articulatory force.
While most languages make use of purely labial phonemes, a few generally lack them.
Examples are Tlingit, Eyak (both Na-Dené), Wichita (Caddoan), and the Iroquoian languages except Cherokee.