The sound /əʊ/, as in home, is a diphthong in Br.E; in Am.E it is closer to being a monophthong.
The sound /ɒ/, as in pot, is pronounced in Am words without lip-rounding, and sounds like the vowel /ɑ:/, as in palm
Many British people pronounce /ɑ:/, a long back vowel, in some words where Americans pronounce /æ/, a short front vowel. Examples: example, can’t, fast, castle, glass, staff, after, pass.
In standard BrE, -r- is only pronounced before a vowel. In AmE, -r- is pronounced in all positions in a word, and it changes the quality of a vowel that comes before it. So words like car, turn, offer sound very different in Br. and Am. speech.
In AmE, -t- and -d- both have a very light voiced pronunciation /d/ between vowels. So, writer and rider sound the same. In BrE, -t- remains unvoiced between vowels.
Before -u and -ew, BrE pronounce n-, d-, and t- like nj/-, dj- and tj-. AmE pronounce them as they are written. Examples are: tune (BrE /tju:n/; AmE /tu:n/), new (BrE /nju:/; AmE /nu:/) Other words are: duke, dew, reduce, tube, nude.. Borough and thorough are pronounced differently. BrE /bʌrə/, /θʌrə/, AmE /bʌrəʊ/, /θʌrəʊ/.Words ending in -tile are pronounced /-tail/ in BrE, and /-tl/ in AmE. Examples: fertile, reptile, futile.
-t- and -d- preceded by -n- are not pronounced in AmE. Examples: twenty /twenɪ/, understand /ʌnəstænd/.
several words which have one main stress in BrE have two in AmE: