What are formants - The elements of phonemes.

In the vowels, F1 can vary from 300 Hz to 1000 Hz. The lower it is, the closer the tongue is to the roof of the mouth. The vowel /i:/ as in the word 'beet' has one of the lowest F1 values - about 300 Hz; in contrast, the vowel /A/ as in the word 'bought' (or 'Bob' in speakers who distinguish the vowels in the two words) has the highest F1 value - about 950 Hz. Pronounce these two vowels and try to determine how your tongue is configured for each.

F2 can vary from 850 Hz to 2500 Hz; the F2 value is proportional to the frontness or backness of the highest part of the tongue during the production of the vowel. In addition, lip rounding causes a lower F2 than with unrounded lips. For example, /i:/ as in the word 'beet' has an F2 of 2200 Hz, the highest F2 of any vowel. In the production of this vowel the tongue tip is quite far forward and the lips are unrounded. At the opposite extreme, /u/ as in the word 'boot' has an F2 of 850 Hz; in this vowel the tongue tip is very far back, and the lips are rounded.

F3 is also important is determining the phonemic quality of a given speech sound, and the higher formants such as F4 and F5 are thought to be significant in determining voice quality.