Words that have the same spelling in the English alphabet but different intonations due to accents or dialects would have different spellings in the International Phonetic Alphabet.
The point of the International Phonetic Alphabet is that you can stumble across any new word you haven't heard before, and be able to pronounce it correctly. If you master the International Phonetic Alphabet and, say, stumble across a Mandarin or Russian word spelled using that alphabet, you'll be able to pronounce it.
The International Phonetic Alphabet has a unique "key" (letter) for every sound that the mouth/tongue/throat can produce basically. (Or at least it tried to, it seems extensions to the IPA have been released to account for other "qualities of speech", like tooth gnashing, lisping, sounds make with a left cleft lip and cleft palate... I'm quoting https://en.wikipedia.org/wiki/International_Phonetic_Alphabe... right now).