There is no sure way of any two people saying the same word with precisely the same sound.
In this respect, pronunciation much more closely resembles handwriting than spelling.
In spelling, there are absolute distinctions which can be learnt and imitated with complete
precision: one can know at once whether a word is spelt in a 'standard' way or not. But two
persons' handwriting and pronunciation may both be perfectly intelligible, yet have obvious
differences without our being able to say which is 'better' or more 'standard.'