English Is Missing A Consistent Alphabet
English spelling is so erratic that we rely on makeshift systems to explain how words sound. Because our written letters do not reliably map to our spoken sounds, dictionaries must invent unique notations just so people can pronounce words correctly.
Unlike languages with phonetic alphabets, English has evolved through layers of history that left many words spelled in confusing ways. You cannot look at a new word and feel certain how to say it because the letters often ignore standard rules. This chaos forces us to use special respelling keys in manuals and dictionaries to serve as a guide. It is essentially a workaround for a language that lost its link between sight and sound centuries ago.