Cotcaught merger

The cotcaught merger or LOT–THOUGHT merger, formally known in linguistics as the low back merger, is a sound change present in some dialects of English where speakers do not distinguish the vowel phonemes in "cot" and "caught". "Cot" and "caught" (along with "bot" and "bought", "pond" and "pawned", etc.) is an example of a minimal pair that is lost as a result of this sound change. The phonemes involved in the cot–caught merger, the low back vowels, are typically represented in the International Phonetic Alphabet as /ɒ/ and /ɔ/, respectively (in the U.S., co-occurring with the father–bother merger, as /ɑ/ and /ɔ/). The merger is typical of most Canadian and Scottish English dialects as well as some Irish and U.S. English dialects.

An additional vowel merger, the father–bother merger, which spread through North America in the eighteenth and nineteenth centuries, has resulted today in a three-way merger in which most Canadian and some U.S. accents have no vowel difference in words like "palm" /ɑ/, "lot" /ɒ/, and "thought" /ɔ/.


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 cot–caught merger is completed in the following dialects:

Homophonous pairs
/ɑ/ or /ɒ/ (written a, o, ol) /ɔ/ (written au, aw, al, ough) IPA (using ⟨ɒ⟩ for the merged vowel) Notes
bobble bauble ˈbɒbəl
bock balk ˈbɒk
bod baud ˈbɒd
body bawdy ˈbɒdi
bon bawn ˈbɒn
bot bought ˈbɒt
box balks ˈbɒks
chock chalk ˈtʃɒk
clod Claude ˈklɒd
clod clawed ˈklɒd
cock caulk ˈkɒk
cod cawed ˈkɒd
coddle caudle ˈkɒdəl
collar caller ˈkɒlə(r)
cot caught ˈkɒt
doddle dawdle ˈdɒdəl
don dawn, Dawn ˈdɒn
dotter daughter ˈdɒtə(r)
fond fawned ˈfɒnd
fox Fawkes ˈfɒks
frot fraught ˈfrɒt
god gaud ˈɡɒd
hock hawk ˈhɒk
holler hauler ˈhɒlə(r)
hottie haughty ˈhɒti
hough hawk ˈhɒk
knot naught ˈnɒt
knot nought ˈnɒt
knotty naughty ˈnɒti
mod Maud, Maude ˈmɒd
Moll mall ˈmɒl
Moll maul ˈmɒl
nod gnawed ˈnɒd
not naught ˈnɒt
not nought ˈnɒt
odd awed ˈɒd
offal awful ˈɒfəl Already homophonous in dialects with the lot–cloth split.
Otto auto ˈɒtoʊ
ox auks ˈɒks
Oz awes ˈɒz
pod pawed ˈpɒd
pol Paul ˈpɒl
pol pall ˈpɒl
pol pawl ˈpɒl
Poll Paul ˈpɒl
Poll pall ˈpɒl
Poll pawl ˈpɒl
Polly Paulie, Pauly ˈpɒli
poly Paulie, Pauly ˈpɒli
pond pawned ˈpɒnd
popper pauper ˈpɒpə(r)
poz pause ˈpɒz
poz paws ˈpɒz
respond respawned rɪˈspɒnd
rot wrought ˈrɒt
shone Sean ˈʃɒn
shone Shawn ˈʃɒn
slotter slaughter ˈslɒtə(r)
sod sawed ˈsɒd
Sol Saul ˈsɒl
sot sought ˈsɒt
squalor squaller ˈskwɒlə(r)
stock stalk ˈstɒk
thot thought ˈθɒt
tock talk ˈtɒk
tot taught ˈtɒt
tot taut ˈtɒt
tox talks ˈtɒks
von Vaughan ˈvɒn
wok walk ˈwɒk
yon yawn ˈjɒn

North American EnglishEdit

On this map of English-speaking North America, 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. Based on the work of Labov, Ash and Boberg.[8]

Nowhere is the shift more complex than in North American English. 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. The symbols traditionally used to transcribe the vowels in the words cot and caught as spoken in American English are ⟨ɑ⟩ and ⟨ɔ⟩, respectively, although their precise phonetic values may vary, as does the phonetic value of the merged vowel in the regions where the merger occurs.

Even without taking into account the mobility of the American population, the distribution of the merger is still complex; there are pockets of speakers with the merger in areas that lack it, and vice versa. There are areas where the merger has only partially occurred, or is in a state of transition. For example, based on research directed by William Labov (using telephone surveys) in the 1990s, younger speakers in Kansas, Nebraska, and the Dakotas exhibited the merger while speakers older than 40 typically did not.[9][10] The 2003 Harvard Dialect Survey, in which subjects did not necessarily grow up in the place they identified as the source of their dialect features, indicates that there are speakers of both merging and contrast-preserving accents throughout the country, though the basic isoglosses are almost identical to those revealed by Labov's 1996 telephone survey. Both surveys indicate that, as of the 1990s, approximately 60% of American English speakers preserved the contrast, while approximately 40% merged the phonemes. Further complicating matters are speakers who merge the phonemes in some contexts but not others, or merge them when the words are spoken unstressed or casually but not when they're stressed.

Speakers with the merger in northeastern New England still maintain a phonemic distinction between a fronted and unrounded /ɑ/ (phonetically [ä]) and a back and usually rounded /ɔ/ (phonetically [ɒ]), because in northeastern New England (unlike in Canada and the Western United States), the cot–caught merger occurred without the father–bother merger. Thus, although northeastern New Englanders pronounce both cot and caught as [kɒt], they pronounce cart as [kät].

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. In this case, a distinct vowel shift (which overlaps with the cot–caught merger for all speakers who have indeed completed the cot–caught merger) is taking place, identified as the Don–dawn merger.[11]


According to Labov, Ash, and Boberg,[12] the merger in North America is most strongly resisted in three regions:

In the three American regions above, sociolinguists have studied three phonetic shifts that can explain their resistance to the merger. The first is the fronting of /ɑ/ found in the Inland North; speakers advance the LOT vowel /ɑ/ as far as the cardinal [a] (the open front unrounded vowel), thus allowing the THOUGHT vowel /ɔ/ to lower into the phonetic environment of [ɑ] without any merger taking place.[13] The second situation is the raising of the THOUGHT vowel /ɔ/ found in the New York City, Philadelphia and Baltimore accents, in which the vowel is raised and diphthongized to [ɔə⁓oə], or, less commonly, [ʊə], thus keeping that vowel notably distinct from the LOT vowel /ɑ/.[13] The third situation occurs in the South, in which vowel breaking results in /ɔ/ being pronounced as upgliding [ɒʊ], keeping it distinct from /ɑ/.[13] None of these three phonetic shifts, however, is certain to preserve the contrast for all speakers in these regions. Some speakers in all three regions, particularly younger ones, are beginning to exhibit the merger despite the fact that each region's phonetics should theoretically block it.[citation needed]

African American Vernacular English accents have traditionally resisted the cot-caught merger, with LOT pronounced [ɑ̈] and THOUGHT traditionally pronounced [ɒɔ], though now often [ɒ~ɔə]. Early 2000s research has shown that this resistance may continue to be reinforced by the fronting of LOT, linked through a chain shift of vowels to the raising of the TRAP, DRESS, and perhaps KIT vowels. This chain shift is called the "African American Shift".[14] However, there is still evidence of AAVE speakers picking up the cot-caught merger in Pittsburgh, Pennsylvania,[15] in Charleston, South Carolina,[16] Florida and Georgia,[17] and in parts of California.[17]


The merger, or its initial conditions, began specifically in eastern New England and western Pennsylvania, from which it entered Atlantic Canada and what is now Ontario, respectively. The merger is in evidence as early as the 1830s in both regions of Canada. Fifty years later, the merger "was already more established in Canada" than in its U.S. places of origin.[18] In Canadian English, further westward spread was completed more quickly than in English of the United States.

Two traditional theories of the merger's origins have been longstanding in linguistics: one group of scholars argues for an independent North American development, while others argue for contact-induced language change via Scots-Irish or Scottish immigrants to North America. In fact, both theories may be true but for different regions. The merger's appearance in western Pennsylvania is better explained as an effect of Scots-Irish settlement,[19] but in eastern New England,[20] and perhaps the American West,[21] as an internal structural development. Canadian linguist Charles Boberg considers the issue unresolved.[22] 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.[23]


In London's Cockney accent, a cot–caught merger is possible only in rapid speech. The THOUGHT vowel has two phonemically distinct variants: closer /oː/ (phonetically [ ~ oʊ ~ ɔo]) and more open /ɔə/ (phonetically [ɔə ~ ɔwə ~ ɔː]). The more open variant is sometimes neutralized in rapid speech with the LOT vowel /ɒ/ (phonetically [ɒ ~ ɔ]) in utterances such as [sˈfɔðɛn] (phonemically /ɑɪ wəz ˈfɔə ðen/) for I was four then. Otherwise /ɔə/ is still readily distinguished from /ɒ/ by length.[24]


Outside North America, another dialect featuring the merger is Scottish English. Like in New England English, the cot–caught merger occurred without the father–bother merger. Therefore, speakers still retain the distinction between /a/ and /ɔ/.

See alsoEdit


  1. ^ a b Wells 1982, p. ?
  2. ^ Heggarty, Paul; et al., eds. (2013). "Accents of English from Around the World". University of Edinburgh. Retrieved 2016-12-12.
  3. ^ a b c Labov, Ash & Boberg (2006), pp. 60–1
  4. ^ Gagnon, C. L. (1999). Language attitudes in Pittsburgh: 'Pittsburghese' vs. standard English. Master's thesis. Pittsburgh: University of Pittsburgh.
  5. ^ Dubois, Sylvia; Horvath, Barbara (2004). "Cajun Vernacular English: phonology". In Kortmann, Bernd; Schneider, Edgar W. (eds.). A Handbook of Varieties of English: A Multimedia Reference Tool. New York: Mouton de Gruyter. pp. 409–10.
  6. ^ Labov, Ash & Boberg (2006), p. 218
  7. ^ "Singapore English" (PDF). Retrieved 2016-12-12.
  8. ^ Labov, Ash & Boberg (2006), p. 122
  9. ^ Gordon (2005)
  10. ^ "Map 1". Retrieved 2016-12-12.
  11. ^ Labov, Ash & Boberg (2006), p. 217
  12. ^ Labov, Ash & Boberg (2006), pp. 56–65
  13. ^ a b c Labov, Ash & Boberg (2006), chpt. 11
  14. ^ Thomas, Erik R. (September 2007). "Phonological and Phonetic Characteristics of African American Vernacular English: Phonological and Phonetic Characteristics of AAVE". Language and Linguistics Compass. 1 (5): 450–475. doi:10.1111/j.1749-818X.2007.00029.x.
  15. ^ Eberhardt (2008).
  16. ^ Baranowski (2013).
  17. ^ a b Jones (2020), p. 165.
  18. ^ Dollinger, Stefan (2010). "Written sources of Canadian English: phonetic reconstruction and the low-back vowel merger". Retrieved 2016-03-19.
  19. ^ Evanini, Keelan (2009). "The permeability of dialect boundaries: A case study of the region surrounding Erie, Pennsylvania". University of Pennsylvania; dissertations available from ProQuest. AAI3405374. pp. 254-255.
  20. ^ Johnson, Daniel Ezra (2010). "LOW VOWELS OF NEW ENGLAND: HISTORY AND DEVELOPMENT". Publication of the American Dialect Society 95 (1): 13–41. doi: p. 40.
  21. ^ Grama, James; Kennedy, Robert (2019). "2. Dimensions of Variance and Contrast in the Low Back Merger and the Low-Back-Merger Shift". The Publication of the American Dialect Society. 104, p. 47.
  22. ^ Boberg, Charles (2010). The English language in Canada. Cambridge: Cambridge. pp. 199?.
  23. ^ Herold, Ruth. (1990). "Mechanisms of merger: The implementation and distribution of the low back merger in eastern Pennsylvania". Doctoral dissertation, University of Pennsylvania.
  24. ^ Wells 1982, pp. 305, 310, 318–319


External linksEdit