Acoustic differences between syllable-initial [f] and [θ

Abstract

The consonants [f] and [θ] are notoriously confusable in perception. Consistent with this fact, previous acoustic analyses have failed to demonstrate strong differences between syllables containing the two consonants in syllable-initial position. However, these earlier studies were limited in the numbers of speakers providing samples and in the measurements made. Therefore, five tokens of each of the syllables [f■], [fu], [θ■], and [θu] were recorded by each of eight speakers (four men and four women) and five acoustic properties measured in each syllable in the vicinity of the fricative segment: duration, amplitude, and first spectral moment of the fricative noise, and the frequency of the second and third formants at voicing onset. No consistent differences were observed for the noises themselves. Differences between syllables resided in the second and third formant transitions at voicing onset: frequencies of both formants are lower for [f] vowel than for [θ] vowel, both for males and females and for [■] and [u]. Thus acoustic evidence is provided supporting the perceptual result that the voiced formants provide whatever acoustic information is available for making phonetic judgments of these consonants. [Work supported by research Grant No. 5 R01 DC 00633 from the NIDCD/NIH.]