Cot-caught merger

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Revision as of 12:31, 15 May 2015 by Ghoti (talk | contribs) (/ɑːr/ or /ɔːr/: precision)

In many parts of North America (about half the United States and all of Canada)[1] /ɑː/ and /ɔː/ sound the same. This is in addition to the father - bother merger, where /ɑː/ and /ɒ/ sound the same. This means that caught /ɔː/, cot /ɒ/, father /ɑː/ and bother /ɒ/ have all the same stressed vowel /ɑː/. In this accent /ɔː/ appears only followed by /r/: north, force.

This accent is so prevalent that it is used in Merriam Webster Learner's Dictionary and in Cambridge Dictionaries Online for British English, US label. Note that Cambridge Dictionaries Online list two different American pronunciations, and only the one that is labeled US has the cot-caught merger.

Other names for this merger (better for those who have it) are "LOT - THOUGHT merger" or "PALM - LOT - THOUGHT merger". There is an area in the United States (in New England) where "lot" and "thought" are merged as [ɒ] but "palm"/"father" is different (as [ɑ]). This means that strictly speaking "LOT - THOUGHT merger" and "PALM - LOT - THOUGHT merger" are different concepts.

Sample word Merriam Webster's
Learner's Dictionary
Cambridge Dictionaries
British English - US
Cambridge Dictionaries
American English
Most American Dictionaries
(if they use IPA)
palm, father /ɑː/ /ɑː/ /ɑ/ /ɑ/ /ɑː/
start /ɑɚ/ /ɑːr/ /ɑr/ /ɑr/ /ɑːr/
safari /ɑr/ /ɑːr/ /ɑr/ /ɑr/ /ɑːr/
lot /ɑː/ /ɑː/ /ɑ/ /ɑ/ /ɒ/
sorry /ɑr/ /ɔː/ /ɑr, ɔr/ /ɑr/ /ɒr/
borrow /ɑr/ /ɑː/ /ɑr, ɔr/ /ɑr/ /ɒr/
thought /ɑː/ /ɑː/ /ɔ/ /ɔ/ /ɔː/
cloth /ɑː/ /ɑː/ /ɔ/ /ɔ/ */ or /ɒBrE, ɔːAmE/
north /oɚ/ /ɔːr/ /ɔr/ /ɔr/ /ɔːr/
moral /or/ /ɔːr/ /ɔr, ɑr/ /ɔːr/ /ɔːr/
force /oɚ/ /ɔːr/ /ɔr, oʊr/ /ɔr/ and sometimes /oʊr/ /ɔːr/
glory /or/ /ɔːr/ /ɔr, oʊr/ /ɔr/ and sometimes /oʊr/ /ɔːr/

Sometimes we mark the CLOTH vowel with an asterisk, as follows:

*: These words are pronounced with /ɔː/ in General American.

The cot-caught merger generates very few homophones.

  • bot (computer program; shortening of robot) - bought; collar - caller; cot - caught; don (put clothes on)/Don (nickname of Donald) - dawn/Dawn; stock - stalk;

/ɑː/ in the PALM - LOT - THOUGHT merger

This phonetics article is valid in an area that includes roughly 50% of North America but is not General American, the accent used in television.


start /stɑːrt/


palm /pɑːm/


thought /θɑːt/


lot /lɑːt/



lot /lɑt/

This article is valid in an area in North America where the following words have the same phoneme vowel: "start", "art", "palm", "spa", "lot", "stop", "thought" and "law".

Many people pronounce /ɑː/ and /ɑːr/ with different vowels (e.g. lodge as [lɑdʒ] and large as [lɑːrdʒ]); however since the difference is predictable there is no problem using the same symbol in both cases (e.g. /lɑːdʒ/ and /lɑːrdʒ/).

Common words

Some common words which practice the pronunciation of /ɑː/ include the following:

  • with "a": father - iguana - llama - piñata - wad - wander - want - wash - wasp - watch
  • with "al": almost - already - alter - always - false - salt
"al" as /ɑː/: calm - chalk - palm - talk - walk
  • with "all": ball - call - fall - hall - mall - small - wall - wallet
  • with "ar": are - aren't - arm - art - article - bar - car - charge - dark - department - far - farm - hard - harm - large - market - park - part - party - regard - smart - star - start - warrant - warranty - water
  • with "o": Boston - chocolate - cloth - cost - follow - gone - got - hot - job - long - lost - lot - not - office - on - possible - probably - problem - song - strong - stop - wrong
  • with "oa": abroad - broad
  • with "ough": ought - thought
past tense and past participle: bought - brought - fought - sought - thought
  • with "aw": dawn - flaw - hawk - jaw - law - lawn - raw - saw - shawl - thaw - yawn
  • with "au": auction - August - Aussie - austerity - Australia - Austria - author - autumn - cause - clause - daughter - fault - launch
past tense and past participle: caught - taught
  • /ɑː/ or /ʌ/: what
  • others: heart - cough
  • homophones: bomb - balm; caller - collar; knot - not;

/ɑːr/ or /ɔːr/

See Pronunciation exercises: "orV" and "orrV"

The following 5 words are pronounced with /ɑː/ in this accent:[2]

  • borrow - morrow (shortening of "tomorrow") - sorrow - sorry - tomorrow

The following words (and many others) are pronounced with /ɑː/ by some speakers an with /ɔː/ by others.

  • correspond - Florida - foreign - forest - historical - majority - moral - orange - origin - priority

Anticipated pronunciation difficulties depending on L1


In Latin America American English is taught (the United Kingdom is far away). Spanish speakers tend to pronounce /ɑː/ according to the spelling. They will pronounce "palm" as [pam] and "lot" as *[lot].

See also


  1. William Labov,The Organization of Dialect Diversity in North America, The o/oh merger [i.e. The /ɑː - ɔː/ merger].
  2. Wikipedia, English-language vowel changes before historic /r/ § Historic "short o" before intervocalic R. Retreived 14 May 2015.

External links