The low back merger

The phonemic contrast between /a/, LOT, and /ɔ/ , THOUGHT, has been lost for many speakers in the area described here. This development is the result of an unconditional merger (i.e., one that applies across the board to every phonological context) and creates homophones of pairs such as cot and caught, Don and dawn, and Polly and Paulie. As noted above, the phonetic value of the merged vowel varies between the poles of the historical sources, /a/ and /ɔ/ , but is commonly unrounded, low and quite back. Some sources have treated the merger as a simple shifting of /ɔ/ into [a], but evidence of misunderstandings between merged and unmerged speakers suggests that the phonetic result is more intermediate between [ɔ] and [a]. Hearers who maintain the contrast may perceive a merged speaker’s THOUGHT words as members of the LOT class (e.g., Dawn heard as Don), but the reverse also happens (e.g., copy heard as coffee).

The low back merger has been well known to dialectologists as a feature of eastern New England, where it tends to show a rounded vowel (Kurath and McDavid 1961). It is also well established across Canada. For the region covered, the early linguistic atlas records show the merger in western Pennsylvania and extending westward on either side of the Ohio river. More recent research has shown the merger to be characteristic of the western states. In an early statement about the merger, Labov (1991: 31) suggested it was a “nonurban” feature, and he noted its absence in Los Angeles and San Francisco. His more recent Telsur project shows the merger to be common in Los Angeles though many San Franciscans still maintain a contrast.

In fact, the low back merger appears to be a relatively new development in the West. Johnson (1975) compares Los Angeles natives who were interviewed in 1953 for the Linguistic Atlas of the Pacific Coast with speakers from his own study twenty years later. He found minimal evidence of the merger among the linguistic atlas speakers while in his sample he observed a steady increase in the adoption of the merger across the generations. Labov’s Telsur findings generally confirm this trend and furthermore suggest the merger is spreading geographically into the Upper Midwest as far as Minnesota and into central states such as Kansas and Nebraska. In Missouri, the merger is relatively more common in the western part of the state (e.g., Kansas City) than in the eastern part, though it can be heard in the speech of some younger speakers in St. Louis. The evidence suggests, therefore, that the low back merger is a change in progress and one that is expanding its geographical range.