The Anticlockwise Checked Vowel Chain Shift in modern RP in the twentieth century: Incrementations and diagonal shifts

This paper presents evidence for a chain shift in the checked vowel sub-system of modern RP over one hundred years, based on LMER analysis of over 10000 vowels from 108 speakers with birthdates from 1883 to 1990. The data confirms previously identified gender-differentiated change in F1 and F2 of TRAP, as well as date-of-birth driven incremental change in F1 of KIT, F1 of STRUT, F2 of FOOT, and, for DRESS, an (F2-(2xF1)) diagonal shift by date of birth that follows TRAP’s path. We also present evidence for an active female-driven change in the LOT vowel, an (F2-(2xF1)) diagonal shift towards the close central area of the vowel space. The paper demonstrates differing statistical patterns in these shifts over time, and suggests a possible origin in changes to TRAP early in the 20th century. All data and additional figures for this study are available via OSF.io. on application to the author.