Information Conveyed by Vowels

Most speech sounds may be said to convey three kinds of information: linguistic information which enables the listener to identify the words that are being used; socio-linguistic information, which enables him to appreciate something about the background of the speaker; and personal information which helps to identify the speaker. An experiment has been carried out which shows that the linguistic information conveyed by a vowel sound does not depend on the absolute values of its formant frequencies, but on the relationship between the formant frequencies for that vowel and the formant frequencies of other vowels pronounced by that speaker. Six versions of the sentence Please say what this word is were synthesized on a Parametric Artificial Talking device. Four test words of the form b-(vowel)-t were also synthesized. It is shown that the identification of the test word depends on the formant structure of the introductory sentence. Some psychological implications of this experiment are discussed, and hypotheses are put forward concerning the ways in which all three kinds of information are conveyed by vowels.