The Extended Speech Assessment Methods Phonetic Alphabet (X-SAMPA) is a variant of SAMPA developed in 1995 by John C. Wells, professor of phonetics at University College London. It is designed to unify the individual-language SAMPA alphabets, and extend SAMPA to cover the entire range of characters in the 1993 version of International Phonetic Alphabet (IPA). The result is a SAMPA-inspired remapping of the IPA into 7-bit ASCII.
SAMPA was devised as a hack to work around the inability of text encodings to represent IPA symbols. Later, as Unicode support for IPA symbols became more widespread, the necessity for a separate, computer-readable system for representing the IPA in ASCII decreased. However, X-SAMPA is still useful as the basis for an input method for true IPA.