Prosody Lab

Abstract:
The narrow goal of this research is to develop an analysis of the timing of the English low phrase accent (L-) in H*L-L% and H*L-H% melodies. This is challenging because L- is generally realized as an ‘elbow’ in the F0 trajectory – i.e. a point of inflection rather than a local maximum or minimum – and it is notoriously difficult to locate F0 elbows precisely. I argue that the proper approach to locating tonal targets involves an ‘analysis-by-synthesis’ approach: Given an explicit model of the mapping from tonal targets to F0 trajectories, we can infer the location of targets by fitting that model to observed F0 contours. So a broader goal is the development of a framework for grammars of tonal phonetics. The proposed model analyzes F0 trajectories as the response of a dynamical system to a control signal that consists of a sequence of step functions connected by linear ramps. Tone realization then involves selecting the control signal that yields the F0 trajectory that best satisfies constraints on the realization of tone targets.

This model is used to infer the location of L- and to analyze its distribution. Previous analyses have proposed either that L- occurs at a fixed interval after H*, or that it aligns to a landmark, such as the end of the accented word or the next stressed syllable. The results do not support any of these hypotheses: L- does not occur at a fixed interval after H*, instead it tends to occur earlier when the interval between H* and the first stressed syllable in the following word is shorter (e.g. ‘álien anníhilator’ vs. ‘mínimally manéuverable’), but L- also does not align to that stressed syllable, or any other landmark. This pattern of realization is analyzed as a compromise between two constraints, one enforcing a target duration for the fall from H* to L-, and a second, weaker constraint requiring the fall to be completed before the next stressed syllable, to avoid misinterpretation of L- as an L* pitch accent associated with that syllable (cf. Barnes et al 2010).