From the foregoing we conclude that, to date, there is no clearly demonstrated superiority for the reading process in rate of processing language information from print over what can be accomplished by the auding process in processing language information from speech. Rather, the available data suggest that both auding and reading processes may operate at the same rates of efficiency when the rate of presentation of language material is directly manipulated. This conclusion is consistent with the assertion in the developmental model that reading utilizes the same languaging capabilities as auding. Hence, the rate at which languaging can be executed limits both the rate of auding and subsequently the rate of reading when that skill is acquired.

Speculation on the Rate of Languaging. It is of interest to note that the rates of 250-300 wpm, indicated by the foregoing as more- or-less "maximal" rates for auding and silent reading, correspond closely to the fastest rates at which trained readers can read aloud. This suggests that the same factors which limit rates of reading aloud may limit rates of auding and reading. One factor limiting oral reading is the rate at which articulatory movements can be made. Lenneberg (1967, pp.88-124) discusses various aspects of speech production, including the rate at which articulatory movements (syllables) can be made. He reports that ". . .subjects between the ages of eight to about thirty could speed up production to eight and occasionally even nine syllables per second for the duration of a few seconds; the rate slowed down to about six per second if the alternating movements were to be sustained over more than three or four seconds." (p. 115)

Taking six syllables per second as an efficient level of production gives 360 syllables per minute. Then, assuming 1.42 syllables per word (the average for 33 of the 36 passages scaled for complexity by Miller and Coleman, 1967; Carroll, 1967 describes six passages with an average of 1.44 syllables per word), we obtain a rate of 254 wpm-a rate comparable to the average silent reading rate of high school students (Taylor, 1964). A rate of 300 wpm corresponds to a syllable per second rate of 7.1, midway between Lenneberg's rates of six syllables per second for sustained production, and nine syllables per second for brief durations of production.

There appears, then, to be a close relationship between the rate at which syllables can be produced, and maximal auding and silent reading rates. It is as though, typically, auders and' readers utilize the same mechanisms for decoding spoken or printed language into conceptualizations, as are used in signaling conceptualizations to others via speech.