Vowel duration and the voicing effect across English dialects

The ‘voicing effect’ – the durational difference in vowels preceding voiced and voiceless consonants – is a well-documented phenomenon in English, where it plays a key role in the production and perception of the English final voicing contrast. Despite this supposed importance, little is known as to how robust this effect is in spontaneous connected speech, which is itself subject to a range of linguistic factors. Similarly, little attention has focused on variability in the voicing effect across dialects of English, bar analysis of specific varieties. Our findings show that the voicing of the following consonant exhibits a weaker-than-expected effect in spontaneous speech, interacting with manner, vowel height, speech rate, and word frequency. English dialects appear to demonstrate a continuum of potential voicing effect sizes, where varieties with dialect-specific phonological rules exhibit the most extreme values. The results suggest that the voicing effect in English is both substantially weaker than previously assumed in spontaneous connected speech, and subject to a wide range of dialectal variability.