Wells, A study of the formants of the pure vowels of British English
The results are presented of measurements made on certain vowel sounds. Twenty-five male speakers of British English (Received Pronunciation) acted as subjects. The vowels investigated were those of the words heed, hid, head, had, hard, hod, haw'd, hood, who'd, Hud, and heard.
Vowel sounds are characterized acoustically by formants, which are frequency regions of high energy concentration corresponding to the passbands of the throat and mouth cavities. The frequency and amplitude of each of the lowest three formants of each vowel were investigated by means of the acoustic spectrograph, and their averages (together, in the case of frequencies, with their dispersions) for the 25 subjects calculated. Measurements were also made of the duration of the vowels concerned.
The results obtained, which are summarized in Table 1, are compared with the results of a similar analysis of General American vowels.