Using Angle calculations to demonstrate vowel shifts: A diachronic investigation of the short vowel system in 20th Century RP (UK)

This paper gives an overview of the long-term trends of diachronic changes evident within the short vowel system of RP during the 20th century. more specifically, it focusses on changing juxtapositions of the TRAP, STRUT and LOT, FOOT vowel centroid positions. The paper uses geometric calculations to give precise and replicable representations of the vowel system and the generational changes apparent in the data. While FOOT-fronting is well known in British English (Torgersen 1997), less is known about the historical trajectory of the STRUT vowel in response to the encroachment of the TRAP vowel whose lowering and backing are also well-documented (Wells 1982). The discussion draws out differences between 'phonetic' and 'sociolinguistic' stances on the interpretation of acoustic vowel data in formant plots