Tonal Center of Gravity: A global approach to tonal implementation in a level-based intonational phonology

Recent evidence that pitch-movement shape can influence perceived alignment of rising (LH) pitch accents in several languages appears to challenge the well-established level-based approach to intonation embodied in the AM model, wherein it is typically assumed that the alignment and scaling of welldefined turning points (TPs) in the F0 contour are the primary phonetic correlates of contrastive accent category. Here we present the results of 2 experiments, arguing that a new approach to tonal implementation succeeds in reconciling these apparent contradictions. This approach, based on the notion of a perceptual reference point called Tonal Center of Gravity (TCoG), treats information about contour shape and TP-localization not in ‘either-or’ terms, but rather as two sets of cues working in a fundamentally synergistic way toward a single perceptual end: the alignment and scaling of TCoG. Experiment 1 shows that TCoG-based models can perform better at distinguishing productions of English L+H* and L*+H pitch accents than comparable TP-only-based models; Experiment 2 shows that TCoG is more robust than TP-only-based models to ambiguities in TP localization commonly encountered in F0 signals from natural speech. TCoG is shown to capture key insights of movement-based approaches to intonation, without abandoning the central advantages of level-based approaches like AM.