coarticulatory

Coarticulation is the phenomenon whereby the articulation of a speech segment is influenced by surrounding sounds, producing overlapping articulatory gestures. In fluent speech, movements for adjacent sounds interact rather than occurring in strict sequence. Coarticulation is widely observed across languages and can be examined in terms of timing (when gestures occur) and acoustics (the produced signal). Two main timing patterns are described: anticipatory coarticulation, where a later segment affects the articulation of the current one; and carryover coarticulation, where an earlier segment continues to influence a following segment.

Articulatory contributors include the lips, tongue, velum, and jaw, whose positions and motions adjust to accommodate neighboring segments. Common effects include nasalization of vowels before nasal consonants, changes in vowel quality before different consonants, and lip rounding of vowels before labial or rounded consonants. These adjustments create continuous, fluent speech even though perceived as discrete phonemic units.

Evidence comes from instrumental methods such as electromagnetic articulography, ultrasound imaging, palatography, and MRI, which reveal articulatory trajectories. Acoustic correlates include characteristic formant transitions and spectral changes that listeners use as cues in speech perception. Coarticulation contributes to regional and individual variation and affects how languages are learned, taught, and processed by machines.

Because coarticulation blurs the boundaries among phonemes, it is a central concept in phonetics, speech science, and computational linguistics, underpinning models of continuous speech production and robust speech recognition and synthesis.