The long-term average speech spectrum (LTASS) and some dynamic characteristics of speech were determined for 12 languages: English (several dialects), Swedish, Danish, German, French (Canadian), Japanese, Cantonese, Mandarin, Russian, Welsh, Singhalese, and Vietnamese. The LTASS only was also measured for Arabic. Speech samples (18) were recorded, using standardized equipment and procedures, in 15 localities for (usually) ten male and ten female talkers. All analyses were conducted at the National Acoustic Laboratories, Sydney. The LTASS was similar for all languages although there were many statistically significant differences. Such differences were small and not always consistent for male and female samples of the same language. For one-third octave bands of speech, the maximum short-term rms level was 10 dB above the maximum long-term rms level, consistent across languages and frequency. A "universal" LTASS is suggested as being applicable, across languages, for many purposes including use in hearing aid prescription procedures and in the Articulation Index.

Thirty-two adults with sensorineural hearing loss participated in a short-term auditory training program. The listeners were assigned to one of four matched groups which were equivalent in pure-tone sensitivity, speech-reception threshold, PB discrimination in quiet and in noise, intelligence, age, education, duration of loss, sex, and hearing-aid use. Each group responded during training to a different combination of listening condition (S/N varied or S/N-constant) and speech material (closed-set or open-set response formats). Statistically significant increase in auditory discrimination was shown on the W-22 and Rhyme tests, while the increase revealed by the Semi-Diagnostic test was not significant. Results indicated that the two listening conditions were equally effective. Similarly, the two types of training material brought about equivalent increases in overall speech discrimination. Trends suggested that open-set and closed-set training each had most effect on the respective type of speech discrimination. In addition, improvement in auditory discrimination was associated with those individuals who were oldest, with those who had highest intelligence, and with those who responded to training material at the most intense presentation level. Finally, listeners who reported the most hearing handicap also tended to show the greatest loss in speech reception and in speech discrimination in noise.

A two-year experiment on voice identification through visual inspection of spectrograms was performed with the twofold goal of checking Kersta's claims in this matter [Nature 196, 1253[Nature 196, -1257[Nature 196, (1962'] and testing models including variables related to forensic tasks. The 250 speakers used in this experiment were randomly selected from a homogeneous population of 25 000 males speaking general American English, all students at Michigan State University. A total of 34 996 experimental trials of identification were performed by 29 trained examiners. Each trial involved up to 40 known voices, in various conditions: with closed and open trials, contemporary and noncontemporary spectrograms, nine or six clue words spoken in isolation, in a fixed context and in a random context, etc. The examiners were forced to reach a positive decision (identification or elimination) in each instance, taking an average time of 15 minutes. Their decisions were based solely on inspection of spectrograms; listening to the identification by voices was excluded from this experi- ment. The examiners graded their self-confidence in their judgments on a 4-point scale (1 and 2, uncertain; 3 and 4, certain). Results of this experiment confirmed Kersta's experimental data, which involved only closed trials of contemporary spectrograms and clue words spoken in isolation. Experimental trials of this study, correlated with forensic models (open trials, fixed and random contexts, noncontemporary spectrograms), yielded an error of approximately 6% false identifications and approximately 13% false eliminations. The examiners judged approximately 60% of their wrong answers and 20% of their right answers as "uncertain."This suggests that if the examiners had been able to express no opinion when in doubt, only 74% of the total number of tasks would have had a positive answer, with approximately 2% errors of false identification and 5% errors of false elimination. The different conditions existing between experimental trials of identification or elimination performed by the examiners of this study and the tasks performed by a professional examiner in real cases are discussed.

Speech signals from 16 different anatomical locations were recorded as subjects intoned different vowels at a constant level. Power level analysis was made to determine relative intensity of the signals. It was found that significant difference in intensity exists among the anatomical locations. Some locations of lesser intensity were subjectively evaluated as providing more faithful signals.

No abstract