'''Labialization''' is a [[Secondary articulation|secondary articulatory]] feature of sounds in some languages. Labialized sounds involve the lips while the remainder of the [[Human mouth|oral cavity]] produces another sound. The term is normally restricted to [[consonant]]s. When vowels involve the lips, they are called [[roundedness|rounded]].
The most common labialized consonants are [[Labialized velar consonant|labialized velars]]. Most other labialized sounds also have simultaneous [[velarization]], and the process may then be more precisely called '''labio-velarization'''. The "labialization" of bilabial consonants often refers to '''protrusion''' instead of a secondary articulatory feature [[velarization]]. [pʷ] doesn't mean [pˠ] although [w] refers to a [[labial–velar approximant]].
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In [[phonology]], labialization may also refer to a type of [[Assimilation (linguistics)|assimilation]] process.
