how does the language vary from region to region?
Great Vowel Shift,  Northern Cities Vowel Shift and Canadian Shift have produced differents in regional accents.
English language
Varieties of English vary the most in pronunciation of vowels. The best known national varieties used as standards for education in non-English-speaking countries are British (BrE) and American (AmE). Countries such as Canada, Australia, Ireland, New Zealand and South Africa have their own standard varieties which are less often used as standards for education internationally. Some differences between the various dialects are shown in the table "Varieties of Standard English and their features".

English has undergone many historical sound changes, some of them affecting all varieties, and others affecting only a few. Most standard varieties are affected by the Great Vowel Shift, which changed the pronunciation of long vowels, but a few dialects have slightly different results. In North America, a number of chain shifts such as the Northern Cities Vowel Shift and Canadian Shift have produced very different vowel landscapes in some regional accents.
who are the native speakers of english language England. where is this country located? United Kingdom. how is the language classified? Anglic languages, Frisian languages, Low German/Low Saxon. to which places did it spread? The British Empire had spread English through its colonies and geopolitical dominance and also adopted in parts of North America, parts of Africa, Australasia. is it considered a global language? Yes, regarded as the first world language. what are the three circles of english speaking countries? Philippines, Jamaica, India, Pakistan, Singapore, Malaysia and Nigeria. name its vowels? Received Pronunciation (RP) and General American (GA) vowels. and consonants? Yes, They are grouped as Fortis obstruents, Lenis consonants.
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English language [SEP] Regional variation
Varieties of English vary the most in pronunciation of vowels. The best known national varieties used as standards for education in non-English-speaking countries are British (BrE) and American (AmE). Countries such as Canada, Australia, Ireland, New Zealand and South Africa have their own standard varieties which are less often used as standards for education internationally. Some differences between the various dialects are shown in the table "Varieties of Standard English and their features". English has undergone many historical sound changes, some of them affecting all varieties, and others affecting only a few. Most standard varieties are affected by the Great Vowel Shift, which changed the pronunciation of long vowels, but a few dialects have slightly different results.