I've been observing very closely the way american speakers pronounce the short vowel sound 'a' [æ]. Particularly I've seen that there are basically three allophones: when the sound is "pure" (like in bat, cat, map, tap, fat, apple,...), before the 'm' or 'n' sound (like in understand, fan, man, jam,...), and before the [ŋ] sound (like in rang, hang, bang,...). Now I'm thinking of a third allophone when the sound become before the 'r' sound (like in characterize, paragraph, charity,...). The thing is that I'm not sure if this is really an allophone or people use a different vowel sound. Sometimes I think people pronounce the words using a short vowel a, but also sometimes such a sound is more like a short vowel 'e'. So, the question is, is that a short vowel sound 'a', a short vowel sound 'e', or it depends on dialect? If the answer is that it's always a short vowel sound 'a' then it is an allophone, otherwise could you tell me about some areas where the pronunciation is made by using one sound or the other. Thak you so much. Also I would appreciate any comment from BE speakers.