Introducing Advancing Prosodic Transcription

Understanding the role of prosody in encoding linguistic meaning and in shaping phonetic form requires the analysis of prosodically annotated speech drawn from a wide variety of speech materials. Yet obtaining accurate and reliable prosodic annotations for even small datasets is challenging due to the time and expertise required. We discuss several factors that make prosodic annotation difficult and impact its reliability, all of which relate to variability : in the patterning of prosodic elements (features and structures) as they relate to the linguistic and discourse context, in the acoustic cues for those prosodic elements, and in the parameter values of the cues. We propose two novel methods for prosodic transcription that capture variability as a source of information relevant to the linguistic analysis of prosody. The first is Rapid Prosody Transcription (RPT), which can be performed by non-experts using a simple set of unary labels to mark prominence and boundaries based on immediate auditory impression. Inter-transcriber variability is used to calculate continuous-valued prosody ‘scores’ that are assigned to each word and represent the perceptual salience of its prosodic features or structure. RPT can be used to model the relative influence of top-down factors and acoustic cues in prosody perception, and to model prosodic variation across many dimensions, including language variety, speech style, or speaker’s affect. The second proposed method is the identification of individual cues to the contrastive prosodic elements of an utterance. Cue specification provides a link between the contrastive symbolic categories of prosodic structures and the continuous-valued parameters in the acoustic signal, and offers a framework for investigating how factors related to the grammatical and situational context influence the phonetic form of spoken words and phrases. While cue specification as a transcription tool has not yet been explored as RPT has, it has the potential to provide a level of detail that will be useful in modelling systematic context-governed variation in the implementation of prosodic categories, with applications in automatic speech synthesis and recognition, as well as modelling human speech production and perception. We discuss how RPT and cue specification, particularly when combined, can improve the efficiency and reliability of prosodic transcription and how they can be integrated with expert phonological transcription.

In this article we present a set of arguments in favor of having access to two levels of prosodic representation, broad phonetic and phonological, and the motivations for developing a set of cross-linguistically transparent and consistent labels (e.g., an International Prosodic Alphabet, IPrA) based on the Autosegmental-Metrical (AM) framework and the ToBI notation. Regarding segmental phonology, as well as lexical suprasegmentals (lexical tone and stress), both the use of two levels of representation and the existence of an international phonetic alphabet have proved to be very useful. The same benefits of adopting these conventions are likely to accrue in the study of intonation.

When annotating a speech signal using an autosegmental-metrical model of intonation, transcribers associate portions of the F 0 contour with labels from a finite inventory of tonal categories. In the models we are concerned with here, these categories have the status of phonological units (phonological form), bridging the intrinsic variability of the speech signal (substance) with the intrinsic fuzziness of post-lexical function (meaning). This, together with the relatively small size of the label inventory, precludes a one-to-one relationship between form and substance, and/or between form and function. A Neapolitan Italian corpus of read speech is used to investigate the distributional properties of two pitch accents that have been studied extensively with respect to substance (the alignment of F 0 peaks) and meaning (sentence modality). Although there is a general consensus that peaks in this variety are aligned earlier in declaratives than in interrogatives, evidence is provided of contexts in which the converse is true, i.e., in which interrogative peaks are even earlier than their declarative counterparts. In this respect, interrogatives have a richer internal structure than declaratives. We argue that differences in how variably a prosodic category is encoded can be dealt with in an intonation transcription system, as long as this system relates phonological form (the choice of pitch accent in this case) both to phonetic substance and to meaning in a transparent way.