slabialization

Slabialization is a phonological process in which a speech segment acquires labial features, typically through assimilation with surrounding segments that involve lip involvement, such as rounding or bilabial contact. The term is not widely standardized in phonetics, and many discussions treat slabialization as either a synonym or a broader description of labialization phenomena observed in contact and coarticulation.

There are two common realizations associated with slabialization. In one, a non-labial consonant adopts a bilabial place of articulation (for example becoming [p], [b], or [m]) in certain phonetic environments. In another, the segment retains its place of articulation but acquires labial features such as lip rounding, yielding labialized forms like [tʷ] or [sʷ].

Slabialization can arise by coarticulation with rounded vowels, within a system of labial harmony, or through contact-induced sound change in bilingual or multilingual settings. It is often discussed alongside labialization but is distinguished by emphasizing a labial articulation rather than just lip-rounding.

Typological notes: slabialization is rarely described as a productive, widely attested phonological process in languages; when it appears, it is typically described as an allophonic or restricted pattern rather than a universal feature. See also: labialization, bilabial, coarticulation, assimilation.