Back Vowel Dynamics and Distinctions in Southern American English

Southern American English is spoken in a large geographic region in the United States. Its characteristics include back-vowel fronting (e.g., in goose, foot, and goat), which has been ongoing since the mid-nineteenth century; meanwhile, the low back vowels (in lot and thought) have recently merged in some areas. We investigate these five vowels in the Digital Archive of Southern Speech, a legacy corpus of linguistic interviews with sixty-four speakers born 1886-1956. We extracted 89,367 vowel tokens and used generalized additive mixed-effects models to test for socially-driven changes to both their relative phonetic placements and the shapes of their formant trajectories. Our results reinforce previous descriptions of Southern vowels while contributing additional phonetic detail about their trajectories. Goose-fronting is a change in progress, with greatest fronting after coronal consonants. Goat is quite dynamic; it lowers and fronts in apparent time. Generally, women have more fronted realizations than men. Foot is largely monophthongal, and stable across time. Lot and thought are distinct and unmerged, occupying different regions of the vowel space. While their relative positions change across generations, all five vowels show a remarkable consistency in formant trajectory shapes across time. This study’s results reveal social and phonetic details about the back vowels of Southerners born in the late nineteenth and early twentieth centuries: goose-fronting was well underway, goat-fronting was beginning, but foot remained backed, and the low back vowels were unmerged.