The Universal Atlas of Phonetic Evolution
Back to Matrix [d] → [b] Edit this Data

[b]→[d]Certainty: 2/5Commonality: 1/5

Voiced bilabial plosive to Voiced alveolar plosive

The shift from the voiced bilabial stop [b] to the voiced alveolar stop [d] is known as coronalization — the replacement of a labial articulation with a coronal (tongue-front) articulation. This direction of change is typologically marked: most bilabial-coronal shifts go in the reverse direction (coronalization is rarer than labialization). It occurs most consistently in two contexts: (1) before front vowels, where the tongue body moves forward and can trigger a coronal onset; and (2) in child phonology, where alveolar [d] is an early-acquired stop that sometimes substitutes for the less-visible bilabial [b]. In Southern Bantu languages, alveolar alternants of labial consonants appear in certain morphological environments (e.g., passive constructions with a -w- suffix), yielding [dʒ] or [d] outputs from original [b]. Historically documented cases of b > d as a regular sound law are rare; the change most often appears as a sporadic or morphologically conditioned alternation.

Phonetic Effects

Coronalization, Place Assimilation

Language Examples

[b] in active stem→[dʒ] / [d] in passive— Labial consonants in some Southern Bantu languages shift toward coronal or palatal outputs in morphological contexts such as passive and applicative constructions, a process sometimes called alveolarization in Bantu phonology.
[b]→[d]— Coronal substitution is documented in developmental phonology: alveolar [d] is acquired before bilabial [b] in some children, leading to temporary b → d substitution as a phonological process.

Related Transformations

More Niger-Congo Shifts

Sources & References

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