IPA was developed to deal with the challenges of representing spoken sounds with orthographic symbols. Different orthographic symbols can be used to denote the same sound. For example, the combined sequence of letters ought are pronounced differently in the words through, tough, bough, trough, and though.
Developed in 1888, IPA is now used internationally. It was revised in 1993, and updated in 1996 and 2005. The IPA provides a set of phonetic symbols that represents speech sounds accurately and consistently.