The Old Persian cuneiform script is the latest and arguably simplest version of the cuneiform script, as well as the first to be deciphered. It was used to write the Old Persian language, an Indo-European language spoken in approximately modern-day Iran. Most attestations of the script come from between the fourth and the sixth centuries BC, but there is controversy within the field of ancient Iranian studies over who invented the Old Persian cuneiform script (or perhaps under whom it was invented). The two possibilities are that it was invented under the reign of Cyrus I (559-530 BC) or under the reign of Darius I (522-486 BC). The crux of the argument relies on the interpretation of a set of ambiguous lines in the trilingual (Old Persian, Elamite, Neo-Babylonian) rock inscriptions at Behistun in Iran: one reading of these line, which refers to a tuppi.me “in Aryan that formerly was not,” is as a proclamation that the Old Persian cuneiform script was conscripted by Darius I. The ambiguity of this line rests in the meaning of tuppi.me, which could be interpreted as “text” or as “script.” As it stands, there is no unambiguous evidence to suggest that the Old Persian script existed previous to the reign of Darius, except perhaps that some of the texts seem to be more representative of other inscriptions of Cyrus rather than Darius (Stronach 1990, 195). Regardless, it seems that a scribal community that was proficient in both the cuneiform writing system and the Aramaic script, which became the administrative language of the Persian Empire (including Mesopotamia) in the sixth century BC, invented the Old Persian cuneiform script.
The Old Persian writing system cannot be considered a true alphabet since each sign can be interpreted both syllabically and phonemically. It consists of thirty-six phonographic signs, including the three vowels a, i, and u, as well as seven unique logograms (‘king,’ ‘country,’ ‘earth,’ ‘god,’ and three different signs for ‘Ahuramazda’, the head of the Persian pantheon), several numerical signs, and a word divider sign 𒀹. In several cases, the phonographic sign inventory included multiple signs with the same phonologic value, such as v, m, t, d, n, dʒ, g, and r. In these instances the different signs were only used before certain vowels. In all other cases, each sign represented a particular consonant and any one of the three vowels mentioned above.
Like the Ugaritic alphabetic cuneiform script, Old Persian cuneiform signs are composed of three types of wedges: horizontal 𒀸, vertical 𒁹, and the Winkelhaken 𒌋. It is also written and read from left to right, just as Mesopotamian cuneiform is. See: http://titus.uni-frankfurt.de/personal/jg/unicode/aperstb4.gif
None of the Old Persian sign forms resemble their phonemic counterparts in Mesopotamian cuneiform, with the exception of the sign representing the sound /l/, which is not native to the Old Persian language, being very likely graphically based on the cuneiform sign la.
Coulmas, F. 1996. The Blackwell Encyclopedia of Writing Systems. Oxford, UK: Blackwell Publishers.
Daniels, Peter T., and William Bright. 1996. The World's Writing Systems. New York: Oxford University Press.
Gershevitch, I. 1979. The Alloglottography of Old Persian. Transactions of the Philological Society, 77(1), 114-190.
Kent, R. G. 1953. Old Persian. Grammar, texts, lexicon, 2.
Rogers, H. 2005. Writing Systems: A Linguistic Approach. Malden, MA: Blackwell Pub.
Schmitt, R. 1991. The Bisitun Inscriptions of Darius the Great: Old Persian Text. on behalf of Corpus Inscriptionum Iranicarum by School of Oriental and African Studies.
Stronach, D. 1990. "On the Genesis of the Old Persian Cuneiform Script." Contribution à l'histoire de l'Iran: mélanges offert à Jean Perrot. Comp. F. Vallat. Paris: Editions Recherche sur les Civilisations. 195-203.