(from the city of Accad), the oldest of the known Semitic languages.
Accadian had two dialects, the Babylonian and the Assyrian, for which reason it is often called Babylono-Assyrian (or Assyro-Babylonian). In Accadian, as in other Semitic languages, the root of a word consists only of consonants, mostly three, and the vowels and some added non-root consonants indicate the grammatical relations and determine the meaning of the root. Its writing is based on the ideographic syllabic cuneiform script, borrowed from Sumerian, with its characteristic polyphony of characters, of which there are more than 500. The year 1857 is regarded as the date that the cuneiform script was finally deciphered.