Cot–caught merger

[3] Legend: unrounded • rounded The shift causes the vowel sound in words like cot, nod and stock and the vowel sound in words like caught, gnawed and stalk to merge into a single phoneme; therefore the pairs cot and caught, stock and stalk, nod and gnawed become perfect homophones, and shock and talk, for example, become perfect rhymes.

The presence of the merger and its absence are both found in many different regions of the North American continent, where it has been studied in greatest depth, and in both urban and rural environments.

Labov et al. also reveal that, for about 15% of respondents, a specific /ɑ/–/ɔ/ merger before /n/ but not before /t/ (or other consonants) is in effect, so that Don and dawn are homophonous, but cot and caught are not.

[19] The third situation occurs in the South, in which vowel breaking results in /ɔ/ being pronounced as upgliding [ɒʊ], keeping it distinct from /ɑ/.

[23] However, there is still evidence of AAVE speakers picking up the cot–caught merger in Pittsburgh, Pennsylvania,[24] in Charleston, South Carolina,[25] in Florida and Georgia,[26] and in parts of California.

[26] In North America, the first evidence of the merger (or its initial conditions) comes from western Pennsylvania as far back as the data shows.

The merger's appearance in western Pennsylvania is better explained as an effect of Scots-Irish settlement,[30] but in eastern New England,[28] and perhaps the American West,[31] as an internal structural development.

[32] A third theory has been used to explain the merger's appearance specifically in northeastern Pennsylvania: an influx of Polish- and other Slavic-language speakers whose learner English failed to maintain the distinction.

[33] Outside North America, another dialect featuring the merger is Scottish English, where the merged vowel has a quality around [ɔ̞].

On this map of English-speaking North America, based on data from the 2006 Atlas of North American English , the green dots represent speakers who have completely merged the vowels of cot and caught . The dark blue dots represent speakers who have completely resisted the merger. The medium blue dots represent speakers with a partial merger (either production or perception but not both), and the yellow dots represent speakers with the merger in transition. [ 14 ]