cot-caught merger

• (US, without the merger) IPA^(key): /ˈkɑt kɔt ˌmɚd͡ʒɚ/
• (US, cot–caught merger) IPA^(key): /ˈkɑt kɑt ˌmɚd͡ʒɚ/
• (UK) IPA^(key): /ˈkɒt kɔːt ˌmɜːd͡ʒə/
• (General New Zealand) IPA^(key): /ˈkɔt koːt ˌmɵːd͡ʒɘ/

cot-caught merger (uncountable)

1. (phonology) A phonemic merger in some varieties of English (especially American and Canadian English) in which the vowels in words such as "hot" and "doll" (/ɒ/) and in words such as "law" and "talk" (/ɔː/) are pronounced identically, making the words "cot" and "caught" homophones.
   • 2011, Scott F Kiesling, Linguistic Variation and Change, page 81:

     One was /au/-monophthongisation, described earlier in Chapter 2, while the second was the so-called low-back merger (LBM), also referred to as the cot–caught merger because words in these two classes are pronounced the same and speakers cannot hear any small differences in their pronunciation, even when they are present.

• low back merger