palatography

Palatography is a set of techniques used to study tongue–palate contact during speech. It encompasses traditional contact palatography (CP) and modern electronic palatography, notably electropalatography (EPG). In CP, a palatal plate is fitted to the roof of the mouth and coated with a reversible dye or paste. As the speaker articulates, the tongue contacts the palate and displaces the coating at contact points. After speech, the plate is examined to reveal a map of contact areas, providing a static snapshot of articulation for a given utterance or phoneme.

EPG uses a custom-fitted, transparent palatal plate embedded with an array of miniature electrodes. When the tongue touches the palate, electrical circuits are completed and the contacts are recorded in real time. EPG yields time-aligned contact patterns, enabling detailed analysis of the timing and coordination of articulations across phonemes and syllables. It is widely used in phonetic research as well as in clinical speech therapy, including work with cleft palate, cerebral palsy, and apraxia.

Applications include analysis of consonant articulation, coarticulation, and cross-language variation; evaluation of speech therapy progress; and validation of articulatory models for speech synthesis. Limitations include the requirement for a custom-fitted palate device, potential discomfort, and the fact that contact maps reflect contact location rather than full tongue shape or movement. Palatography is often complemented by other imaging methods such as ultrasound or MRI, including MRI-compatible EPG.

See also electropalatography; ultrasound palatography.