The generation of nasal consonants can be simulated approximately by a cascade connection of simple electrical tuned circuits excited by a quasi-periodic electrical buzz source. The lowest resonance for nasal consonants is in the vicinity of 200 to 300 cps, and the damping of this resonance is greater than that for the first resonance of vowels. A terminal-analog synthesizer and control device have been used to generate a number of synthetic syllables, each consisting of a nasal consonant followed by a vowel, with smooth formant transitions between consonant and vowel portions. Systematic listening tests have shown that the identification of the nasal consonant is determined largely by the frequency position of the second resonance of the nasal portion of the syllable, and thus by the direction and extent of the second formant transition of the vowel, as noted in other studies. The identification of the nasal consonant is also dependent to some extent on the duration of the consonant and transition portions of the syllable. Isolated nasal consonants generated by this procedure can also be identified with reasonable consistency. HE principal objective of the present study is to attempt to gain some insight into the acoustic cues that are important for the identification of nasal consonants. A secondary objective is to determine whether, with slight modification, a simple terminalanalog synthesizer of the type normally used to generate vowels can synthesize acceptable nasal consonants. Technology. 1Hattori, Yamamoto, and Fujimura, J. Acoust. Soc. Am. 30, 267-274 (1958). • C. G. M. Fant, "Acoustic theory of speech production," Tech. Rept. No. 10, Speech Transmission Laboratory, Royal Institute of Technology, Stockholm (1958) (to be published by Mouton and Company, The Hague, 1959). have been reported previously. The perceptual study carried out at the Haskins Laboratories a used as stimuli nasal consonants synthesized by a pattern playback device. The results of that study indicated that (1) a synthetic nasal consonant can be distinguished from other members of its class on the basis of the transition of the second formant of the adjacent vowel, and (2) acceptable nasal consonants can be synthesized on the pattern playback by generating three "neutral" formants that are of lower intensity than those of:the adjacent vowel. In the present investigation the perception of nasal consonants, both in isolation and in consonant-vowel syllables, is examined by obtaining responses of listeners to synthetic speech stimuli. Analog techniques a Liberman, Delattre, Cooper, and Gerstman, Psychol. Monographs 68.8, 1-13 (1954). 4 In a footnote in their paper, Liberman et al. a indicate that the frequency positions of the "nasal" formants may, in actual speech, be characteristically different for/m/, /n/, and/r,I/, although a single neutral sound was used in their perceptual tests. 661
