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FORMANT

المؤلف:  John Field

المصدر:  Psycholinguistics

الجزء والصفحة:  P115

2025-08-24

701

FORMANT

A concentration of acoustic energy within a narrow frequency band in the speech signal. The vocal tract acts as a resonator: it responds to the vibration of air from the lungs at particular frequencies, depending upon its current shape. This creates bands of intensity in the sound that is produced, which show up as dark bars on a spectrogram.

Three of these formants, numbered by frequency as F1 (the lowest), F2 and F3, are sufficient to distinguish a vowel. For a pure ‘steady-state’ vowel, they appear on a spectrogram as parallel horizontal bars. A front vowel is indicated by a wide gap between F1 and F2 while a back vowel is indicated by a narrow one.

Consonants are distinguished by a formant transition from the obstruction used to form the consonant to the steady position which marks the succeeding vowel. There is usually sufficient information in F2 to distinguish the consonant. However, a problem for research into speech perception is that the F2 formant transition of a given consonant varies considerably according to the vowel that follows. (See Figure F1.)

See also: Speech perception: phoneme variation

Further reading: Ball and Rahilly (1999); Denes and Pinson (1993); Pickett (1999)