A pangram or holoalphabetic sentence is a sentence using every letter of a given alphabet at least once. Pangrams have been used to display typefaces, test equipment, and develop skills in handwriting, calligraphy, and keyboarding. Pangrams exist in every alphabet-based language. The best-known English pangram is "The quick brown fox jumps over the lazy dog." It has been used since at least the late 19th century, was utilized by Western Union to test Telex / TWX data communication equipment for accuracy and reliability and is now used by a number of computer programs (most notably the font viewer built into Microsoft Windows) to display computer fonts.