car, father, jarring ■ man, lad, mast
A British guy would pronounce the vowel "a" equally in all these words. But an American would give one sound for the first three words, and the other for the rest.
It is interesting to me, that the American English has changed the Brithsh sound "a" in most of the words, but retained it intact in a handful of words.
This leads to a conclusion so there are probably more vowel sounds in the American English.