Conventional, biological and environmental factors in speech communication: a modulation theory.

Speech signals contain various types of information that can be grouped under the headings phonetic, affective, personal and transmittal. Listeners are capable of distinguishing these. Previous theories of speech perception have not considered this fully. They have mainly been concerned with problems relating exclusively to phonetic quality. The theory presented in this paper considers speech signals as the result of allowing conventional gestures to modulate a carrier signal that has the personal characteristics of the speaker, which implies that in general the conventional information can only be retrieved by demodulation.