Yi Xu
University College London

Yi Xu

University College London
United Kingdom

Duration in speech from an articulatory-functional perspective

Speech happens in time and duration is a critical aspect of timing in speech. There has been much research of various duration phenomena at different levels, yet there is a lack of a coherent account that that links them together. In this tutorial I explore duration from an articulatory-functional perspective that views speech as an information system that encodes multiple layers of communicative functions through an articulation process (Xu, 2009). From this perspective, duration is both intrinsic (Fowler, 1980), i.e., bound by articulatory constraints, and extrinsic (Turk & Shattuck-Hufnagel, 2020), i.e., functionally controlled to encode information.

Intrinsically, the demand to transmit information as efficiently as possible often pushes the speed limit of articulation, resulting in reduced intelligibility due to undershoot of phonetic targets (Xu & Prom-on, 2019). The need for articulatory clarity against this intrinsic constraint gives rise to a positive correlation between duration and importance of information (Xu, 2019). This correlation seems to also form a phonetic basis (Fowler & Housum, 1987; Wang et al., 2018) for the negative relation between word frequency and word length (Piantadosi et al., 2011). Extrinsically, duration is actively used as a dimension for encoding communicative functions, including, in particular, lexical contrast, grouping/boundary marking and emotional/functional expressions (Xu, 2019).

In addition to the abovementioned well-defined durational functions, there is also a weak tendency toward isochrony of syllables and prosodic phrases. But the tendency is language-dependent, based on data from English and Mandarin (Wang et al., 2018; Xu & Wang, 2009), and in a direction opposite of the widely known rhythm class hypothesis (Abercrombie, 1967).

This articulatory-functional view of duration may offer a coherent account that can link up many reported duration phenomena. But many further questions remain to be resolved by further research.