Production and perception of prevelar merger: Two-dimensional comparisons using Pillai scores and confusion matrices

Vowel merger production is quantified with gradient acoustic measures, while phonemic perception methods are often coarser, complicating comparisons within mergers in progress. This study implements a perception experiment in two-dimensional formant space (F1 × F2), allowing unified plotting, quantification, and statistics with production data. Production and perception are compared within 20 speakers for a two-part prevelar merger in progress in Pacific Northwest English, where mid-front /ɛ, e/ approximate or merge before voiced velar /ɡ/ (leg-vague merger), and low-front prevelar /æɡ/ raises toward them (bag-raising). Distributions are visualized with kernel density plots and overlap quantified with Pillai scores and confusion matrices from linear discriminant analysis models. Results suggest that leg-vague merger is perceived as more complete than it is produced (in both the sample and community), while bag-raising is highly variable in production but rejected in perception. Relationships between production and perception varied by age, with raising and merger progressing across two generations in production but not perception, followed by younger adults perceiving leg-vague merger but not producing it and varying in (minimal) raising perception while varying in bag-raising in production. Thus, prevelar raising/merger may be progressing among some social groups but reversing in others.