Hearing and the development of language and speech.

The criticality of hearing is discussed in relation to language and speech development in children. The fundamentals for such development, the significant milestones in normal language and speech acquisition, and a delineation of the deleterious effects of significant hearing loss on the development of expressive and receptive oral communication are presented.

Ratings of vocal pleasantness and the aging process.

In response to the questions raised at the outset, the following summary statements can be made: (1) Listeners were reliable in making pleasantness judgments. All listening groups were reliable, but the two older listening age-groups had the highest correlation coefficients. (2) Speakers were judged as less pleasant as their age levels increased. (3) Young listeners made judgments nearer the unpleasant end of the scale than did the older listeners. (4) Male speakers were judged as more pleasant than were female speakers. (5) Female listeners rated speakers as being more pleasant than did the male listeners.

Clues to aural discrimination.

Five measures of the items of the Multiple-Choice Intelligibility Test were obtained: apparent aural similarity of the four words available to a listener on hearing a stimulus, interconsonantal differences among the prevocalic portions of these words, phonemic discrepancies among these words, distinctive feature differences among these words, and the pooled discrimination score of the four words that were available to the responder on hearing the stimulus. The last score was made the target in a multiple correlation problem, and the relative contribution, combined and separately, of the four remaining measures to the target measure was determined. These four measures accounted for approximately 45% of the variance among the scores of discrimination. The strongest contributors were apparent aural similarity of the available responses and the phonemic discrepancy among the available responses.

The effects of duration, frequency, and loudness upon the reproduction of temporal intervals.

Subjects (five normal hearing graduate students in the Department of Audiology) were asked to reproduce temporal intervals of 1, 3, 5, 7, and 9 sec. The intervals were filled with pure tones at frequencies of 250, 500, 1000, 2000, and 4000 Hz and at loudness levels of 40, 50, 60, 70, and 80 phons. The reproductions were transformed into the ratio DT/T, where DT represents the difference-time between the stimulus duration and the duration of the reproduction, and T represents the stimulus duration. It was found that neither frequency nor loudness had any significant effect upon the ability to reproduce the durations. The only significant variable was duration. There were no significant interactions among the variables. On the average, the durations of 1 and 3 sec were overestimated and the durations of 7 and 9 sec were overestimated. The duration of 5 sec was neither overestimated nor underestimated, the indifference point falling at 4.90 sec.