Exploring the anatomy of articulation rate in spontaneous English speech: relationships between utterance length effects and social factors

TL;DR

This study investigates how utterance length and social factors like age and gender influence speech rate in spontaneous English, revealing that utterance length has the strongest effect, while social effects are smaller and context-dependent.

Contribution

It models speech rate across multiple corpora, demonstrating that utterance length dominates and social factors have smaller, consistent effects on speech rate.

Findings

Utterance length has the largest effect on speech rate.

Social factors like age and gender have smaller, modulating effects.

Effects of utterance length are consistent across speakers and corpora.

Abstract

Speech rate has been shown to vary across social categories such as gender, age, and dialect, while also being conditioned by properties of speech planning. The effect of utterance length, where speech rate is faster and less variable for longer utterances, has also been shown to reduce the role of social factors once it has been accounted for, leaving unclear the relationship between social factors and speech production in conditioning speech rate. Through modelling of speech rate across 13 English speech corpora, it is found that utterance length has the largest effect on speech rate, though this effect itself varies little across corpora and speakers. While age and gender also modulate speech rate, their effects are much smaller in magnitude. These findings suggest utterance length effects may be conditioned by articulatory and perceptual constraints, and that social influences on speech rate should be interpreted in the broader context of how speech rate variation is structured.