Embryological considerations of distinctive feature theory.

The role of the physiology is emphasized here, perhaps to the eventual denial of the importance of the acoustic cues involved at these stages. The acoustic cues are the result of the physiology and are a further development of the features of speech. The selection of the sounds of babbling is a function of the physiological readiness and is an internal function [Locke, 1983]. Sounds are produced that are not used in final adult speech [Locke, 1983]. It is the acoustic cues of the environment that perhaps cause the 'babbling drift' toward adult speech of the environment [Brown, 1958]. In line with the above-mentioned ideas regarding branchial arch development, most of the components of the outer and middle ear are derivatives of the first branchial arch, which though limited musculature is involved, especially for sound perception, might downplay the role of acoustics at these earliest stages even further. If it can be said that cortical organization and representation development follow a similar sequence as is evidenced from the branchial arches and their derivatives, the importance of acoustic stimuli, at this point, would be even further questioned for these early stages. The assumption should be made that a muscle or muscle group does not function prior to this established branchial arch pair sequence. The major distinction here has been utilization of the structures in a 'conscious', deliberate, voluntary manner with a specific goal in mind. The babbling and even feeding that children undergo provides evidence that these structures function perhaps long before any sequence of branchial arch pair developmental sequence can be applied.(ABSTRACT TRUNCATED AT 250 WORDS)