A word can be spoken in different ways by different individuals, depending on many factors, such as the time in which they grew up, the area in which they grew up, the area in which they now live, their social class, and their education. Note that the word is spelled pronunciation, not pronounciation.
Linguistic terminology
The way in which an individual pronounces words depends firstly on the basic units of sound (phones) that they use in their language. The branch of linguistics which studies these units of sound is phonetics. Phones which play the same role are grouped together into classes called phonemes; the study of these is phonemics.
In lowland South Carolina, in coastal Georgia and Florida, and occasionally elsewhere \A\ is pronounced as a monophthong.
In Received Pronunciation \r\ is sometimes pronounced as a flap in the same contexts in which \t\ and \d\ occur as flaps in American English.
In these dialects r is pronounced as a nonsyllabic \and\ when it occurs in these positions or there may be no sound corresponding to the r, thus beard, corn, and assured may be pronounced as \'biandd\, \'koandn\, and \and-'shuandd\ or, usually with some lengthening of the vowel sound, as \'bid\, \'kon\, and \and-'shud\.