Volume 40, Issue 3

An algorithm is presented which detects quasi-periodic parts in a given speech signal, and provides the fundamental frequency for these parts. The algorithm analyses the structure of the time-amplitude representation of the speech signal. It first determines potential ‘period-twins’ and then observes whether these period-twins are members of a ‘period-chain’. The performance of the algorithm is evaluated. The results are given as absolute and relative figures and are compared with other methods.

Building on the results of a previous study, reiterant speech is used to test a number of durational characteristics of a stress-timed language (English), a syllable-timed language (Spanish) and a mora-timed language (Japanese). The results indicate that moras and stress feet do influence syllable duration in their respective languages, Japanese and English. Spanish, however, seems to show no language-specific durational characteristics which could be claimed to be indicative of syllable timing.

The purpose of this study was to compare the phonological and acoustic-phonetic structure of spontaneous versus imitative speech. 10 children (2:3 to 3:8) were recorded producing words spontaneously and imitatively. Correct productions of consonant clusters and voice onset time were compared for the two speech modes. On these two measures, there were no differences between words produced imitatively and spontaneously.

The relationship between experimental method and the perception hypothesis being examined is a particularly critical one. Here, earlier studies employing the click-placement method are surveyed, and the conclusions drawn there about the perceptual processes involved are discussed. A working hypothesis is developed which enables an examination, for the first time, of Ladefoged and Broadbent’s [1960] original claim concerning basic processing units. Within a hypothetical framework of hierarchically organized perceptual decisions, the click-placement task is applied in a series of experiments designed to approach the question of processing units at segment, syllable and foot level. Evidence is found for the psychological reality of the syllable and foot. The phonetic basis of the foot is examined and found to be replaceable by top-down information. Between foot and syllable level, indications of differential word demarcation were found, dependent on differences in segmental structure.