sentences:  The "coil"–"curl" or "oil"–"earl" merger is a vowel merger that historically occurred in some non-rhotic dialects of American English, due to an up-gliding vowel.The "mare"–"mayor" merger is a process occurring in many varieties of British English, as well as the Philadelphia dialect and Baltimorese, where bisyllabic is pronounced as the centering diphthong in many words.In these varieties, "mayor" is pronounced , homophonous with "mare".