A sounds like /uh/ as in [but]
When letter A is the initial, and only, sound in multi-syllable word: (a/wake, a/gain, a/head, a/greed, a/go, a/way, a/long, a/round, a/cross, a/mount, a/lone, a/fraid, a/rrive)
A sounds like /ah/ as in [hot, father]
These combinations:
A+W, or W+A (saw, water, draw, wash, watch, walk, what, wall, law, wasn’t, wash)
A+L = ah (always, plural, usually, numeral, fall, general, wall, tall, already, signal, equal, decimal, capital, mammal) (except prefixes that change meaning, e.g. mal-)
A+R = ah (far, car, start, farm, appear)
A sounds like /æ/ as in [bat]
When letter A is the first of two letters in one-syllable words: am, as, at, ad
When letter A is in the same syllable with, and precedes:
A+M: am, amicable, mammogram, mammal
A+K-sounds: accept, actually, factories, practice, exactly, act, factors, fact, back
A+D: adjective, bad, add
A+N: an, than, man, and, triangle, chance, plan, plants, sand, bank, angle, dance, can, can’t, language, thousand, ran, understand, animal, answer, began, fancy
A+P: apple, capital, captain, happy, map, sap, tapestry (except words where p is followed by final –e, ex: “tape”)
AT: at, sat, fat, cattle, flat, hat, matter
AS; AST, ASK: fast, class, gas, pass, glass, ass, ask, last, master
ATH: path, fathom
A+F-sounds: graph, after
When letter A is in the same syllable with, and follows:
V+A value, valley, valor, vampire, valuate, vamp, vanity (exception: some VA is pronounced /vey/, as in vacation, vacant, vacate), but VA is never pronounced /vä/
TRA tractor, trance, travel, transit, tradition, trampoline (unless A is followed by W, e.g. trawl, then it reverts to /ä/)