PHILOSOPHY OF PHONETIC TRASCRIPTION
In English there is no one-to-one correspondence between spelling and sound. In English, the written form cat represents the spoken form of this word, viz the k-sound, illustrating this point from English, a letter of the alphabet may stand for different sounds or combinations of sounds, in different words, and conversely, a given sound may be represented by different letters, or combinations o letters, in different words.
Because of mismatch between spelling and sound, a learner of a language like English cannot be sure how to pronounce a word that he encounters for the first time in the written form. To overcome the problem International Phonetic Alphabet (IPA) is devised, claimed to have symbols to represent all the sounds.