Variation in the Formant in Nigerian English Vowels

The study investigates the dynamic spectral properties of vowels in Western Nigerian English (WNE), moving beyond traditional mid-point analyses commonly used in Nigerian English (NE) research. Using a sample of 75 WNE speakers from the west, east, and north of Nigeria, the study examines lexical sets of TRAP/BATH, KIT/FLEECE, and FOOT/GOOSE. By applying two-point and nine-point acoustic measurements and analyzing formant dynamics (including vector length, trajectory length, formant velocity, and trajectories) through Generalized Additive Mixed Models (GAMMs), the study shows evidence of phonetic differences in WNE vowel production. The results highlight significant regional, social and linguistic effects, showing that speakers from the north and west produce vowels with longer trajectory lengths than those from the east, which challenges prior assumptions that WNE lacks tense–lax phonetic contrasts.