Role of f0 alignment in distinguishing intonation categories: evidence from American english

Laura C Dilley,Christopher C Heffner

doi:10.20396/joss.v3i1.15039

Abstract

Under the autosegmental-metrical (AM) theory of intonation, the temporal alignment of fundamental frequency (F0) patterns with respect to syllables has been claimed to distinguish pitch accent categories. Several experiments test whether differences in F0 peak or valley alignment in American English phrases would produce evidence consistent with a change from (1) a H* to a H+L* pitch accent, and (2) a L* to a L+H* pitch accent. Four stimulus series were constructed in which F0 peak or valley alignment was shifted across portions of short phrases with varying stress. In Experiment 1, participants discriminated pairs of stimuli in an AX task. In Experiment 2, participants classified stimuli as category exemplars using an AXB task. In Experiment 3, participants imitated stimuli; the alignment of F0 peaks and valleys in their productions was measured. Finally, in Experiment 4, participants judged the relative prominence of initial and final syllables in stimuli to determine whether alignment differences generated a stress shift. The results support the distinctions between H* and H+L* and between L+H* and L*. Moreover, evidence consistent with an additional category not currently predicted by most AM theories was obtained, which is proposed here to be H*+H. The results have implications for understanding phonological contrasts, phonetic interpolation in English intonation, and the transcription of prosodic contrasts in corpus-based analysis.

Highlights

A number of studies of speech prosody—that is, variations in fundamental frequency, intensity, and timing in speech—have attempted to explain the ways that prosody can be used to signal differences in meaning, paralleling early studies in segmental phonology
Each stimulus series was based on distinct words with specific stress patterns suited to testing either peak-related or valley-related accent categories, based on stress patterns outlined in Section 1.1 and represented in idealized form in Figure 1 which may be ambiguous according to current AM theories of tonal phonology
Higher-sensitivity participants showed classification curves based on generalization data which were more s-shaped than lower-sensitivity participants

Summary

Introduction

A number of studies of speech prosody—that is, variations in fundamental frequency (cf. pitch), intensity, and timing in speech—have attempted to explain the ways that prosody can be used to signal differences in meaning, paralleling early studies in segmental phonology. Smaller differences in F0 alignment have often been shown to be associated with various kinds of phonetic or contextual factors, including differences in vowel duration, speech rate, location of word boundaries, stress clash, syllable affiliation, dialect, and others [7,8,9, 13, 15,16,17,18,19] These fine-grained, gradient F0 alignment differences have generally not been shown to affect meaning or representation and are instead considered to arise from differences of phonetic implementation, rather than phonological representation [17,18,19]

Methods

Results

Conclusion