Thinking probabilistically in the study of intonational speech prosody

Abstract

Speech prosody, the melodic and rhythmic properties of a language, plays a critical role in our everyday communication. Researchers have identified unique patterns of prosody that segment words and phrases, highlight focal elements in a sentence, and convey holistic meanings and speech acts that interact with the information shared in context. The mapping between the sound and meaning represented in prosody is suggested to be probabilistic—the same physical instance of sounds can support multiple meanings across talkers and contexts while the same meaning can be encoded in physically distinct sound patterns (e.g., pitch movements). The current overview presents an analysis framework for probing the nature of this probabilistic relationship. Illustrated by examples from the literature and a dataset of German focus marking, we discuss the production variability within and across talkers and consider challenges that this variability imposes on the comprehension system. A better understanding of these challenges, we argue, will illuminate how the human perceptual, cognitive, and computational mechanisms may navigate the variability to arrive at a coherent understanding of speech prosody. The current paper is intended to be an introduction for those who are interested in thinking probabilistically about the sound-meaning mapping in prosody. Open questions for future research are discussed with proposals for examining prosodic production and comprehension within a comprehensive, mathematically-motivated framework of probabilistic inference under uncertainty.