Vocalic mergers tend to be regionally restricted. Among a number of ongoing or recent processes, the following seem noteworthy and have been discussed in the literature:

– the “Northern Cities Shift”, a chain shift of vowels in urban centers of the northern US;

– the “Southern Shift”, a pattern of interrelated vocalic changes that has been observed in the Southern US and in a few southern hemisphere countries;

– the merger of TRAP and BATH, merging to the low vowel in Scotland and northern England, in parts of the Caribbean, in West African, and in the Pacific, and to the raised one throughout North America and in the Philippines;

– homophony between FOOT and GOOSE, to be found in Scotland (and, with restrictions, in other British dialects), in West Africa, South-East Asia, and the Pacific region:

– the merger of LOT and THOUGHT, spreading in much of inland-northern and western North America, and also occurring in ScE, some British dialects, West and East Africa, Asia, and the Pacific;

– STRUT merging with LOT, predominantly in Jamaica, Nigeria, and Cameroon;

– mergers between Mary, merry, and marry in specific regions of the US (frequently discussed in traditional American dialect geography)

– homophony between KIT and FLEECE, to be found in South-East Asia, in all Pacific contact varieties, and in much of West Africa;

– the merger of NEAR and SQUARE (typically exemplified by ear/air) in New Zealand, shared with part of East Anglia and restricted occurrences elsewhere.

Pre-nasal and pre-lateral environments tend to strongly promote vocalic mergers (e.g. pin – pen in SAmE and, less regularly, elsewhere; TRAP – DRESS before /l/ in South Africa, Australia and New Zealand). The same applies to positions before /r/, though in this case the issue of rhoticity plays an even more prominent role. Nasalization of vowels before nasals is reported mainly from North America and some countries in West Africa. Vowel harmony phenomena are uncommon but documented for some Caribbean and West African contact varieties, notably in Jamaica and Cameroon. The “Scottish Vowel Length Rule”, specifying the lengthening of certain vowels in some environments, can also be found in Orkney and Shetland as well as in Newfoundland. The effect of spelling pronunciation in the phonetic realization of unstressed vowels shows in some African and Asian, Caribbean, and even British varieties.