Vowel Formants

Vowels can be represented by their frequencies. They have a different distribution of acoustic energy. Their formant values are the acoustic resonances of the vocal tract and are represented as dark bands in a spectrogram. Each vowel can be identified by the unique frequencies of the first and second formants.

Here are the approximate values of the first and second formants of five vowels:

[u] F1 300 Hz F2 800 Hz
[o] F1 500 Hz F2 1000 Hz
[i] F1 320 Hz F2 2500 Hz
[e] F1 500 Hz F2 2300 Hz
[a] F1 1000 Hz F2 1400 Hz

The low vowel [a] has the highest frequency at the first formant, but at the second formant, the vowel [i] has the highest. The high back vowel [u] has the lowest frequency at both formants. The vowel with the greatest difference in frequency between the two formants is [i].

In addition to articulatory characteristics, vowels can also be identified by their acoustic properties. All vowels have a different distribution of acoustic energy. Their formant values vary from speaker to speaker. However, the frequencies of the first and second formants are sufficient to identify every vowel.