Various organs of the speaker are in motion while he pronounces any one sound, and the resulting sound wave can be described as the resultant of waves of various frequencies. It would thus be possible to set up elements representing individual movements of organs involved in speech, or simple waves of various relative frequencies, and identify the phoneme as a simultaneous combination of these elements. Furtermore, such elements could be so defined that each phoneme should not be composed of unique elements, but rather should consist of a different combination of a few out of a limited stock of these elements. Thus, the English sounds represented by [v] and [z] normally involve vibration of the speaker’s vocal chords, which is not the case for [f] and [s]; [v] and [z] have a feature in common which is absent in [f] and [s] and which is noticeable, for instance, in the fact that [v] and [z] can be heard at much greater distances (everything else being equal) than [f] or [s].
- Harris (1951), Pag. 143