Formant

A concentration of acoustic energy around a particular frequency in the speech signal, produced by the resonance of the vocal tract. Formants are labeled sequentially (F1, F2, F3, etc.) from lowest to highest frequency and are key to distinguishing different vowel sounds and some consonants. The first two formants (F1 and F2) are most important for vowel identification, while higher formants contribute to voice quality and speaker identity. In speech analysis research for accessibility, formant patterns help characterize the speech production differences between neurotypical speakers and individuals with conditions such as autism spectrum disorder or Down syndrome, informing the design of speech therapy tools and assistive technologies.