Prenasalization

Prenasalization is a phonological feature in which a nasal segment precedes the main consonant in the same onset, resulting in what are commonly called prenasalized stops. In many languages these sequences are treated as single phonemes, while in others they are analyzed as a nasal plus stop cluster. The most typical prenasalized stops are mb, nd, and ŋɡ, formed from a nasal closure such as [m], [n], or [ŋ] followed by an oral stop like [b], [d], or [ɡ].

Phonetically, prenasalized consonants often involve a brief nasal phase before the oral release of the stop. In many descriptions they behave as a unit with a place of articulation that matches the following stop (labial, alveolar, velar). Some languages realize the onset with a clear nasal release, while others merge the nasal and stop more tightly, making the segment feel like a single complex consonant. The nasal portion can influence voice onset time and timing of the release, producing characteristic acoustics different from plain stops or plain nasals.

Typologically, prenasalized consonants are widespread, especially in Bantu languages such as Swahili and Zulu, but they also occur in other language families around the world. They can be phonemic, contrasting with plain nasals or plain stops, or allophonic, occurring in predictable environments. Some languages have both prenasalized stops and other prenasalized obstruents, while others limit prenasalization to a subset of consonants.

In summary, prenasalization describes a nasal-led onset that creates a prenasalized consonant, notably widespread in the world’s languages and varying in phonemic status and phonetic realization.