The earliest language written in Mesopotamia was Sumerian, an agglutinative language isolate. Along with Sumerian, Semitic dialects were also spoken in early Mesopotamia. Subartuan a language of the Zagros, perhaps related to the Hurro-Urartuan language family is attested in personal names, rivers and mountains and in various crafts. Akkadian, came to be the dominant language during the Akkadian Empire and the Assyrian empires, but Sumerian was retained for administration, religious, literary, and scientific purposes. Different varieties of Akkadian were used until the end of the Neo-Babylonian period. Aramaic, which had already become common in Mesopotamia, then became the official provincial administration language of first the Neo Assyrian Empire, and then the Achaemenid Persian Empire. Akkadian fell into disuse, but both it and Sumerian were still used in temples for some centuries. The last Akkadian texts date from the late 1st century AD.
Early in Mesopotamia's history (around the mid-4th millennium BC) cuneiform script was invented for the Sumerian language. Cuneiform literally means "wedge-shaped", due to the triangular tip of the stylus used for impressing signs on wet clay. The standardized form of each cuneiform sign appears to have been developed from pictograms. The earliest texts (7 archaic tablets) come from the E Temple dedicated to the goddess Inanna at Uruk, from a building labeled as Temple C by its excavators.
The early logographic system of cuneiform script took many years to master. Thus, only a limited number of individuals were hired as scribes to be trained in its use. It was not until the widespread use of a syllabic script was adopted under Sargon's rule that significant portions of Mesopotamian population became literate. Massive archives of texts were recovered from the archaeological contexts of Old Babylonian scribal schools, through which literacy was disseminated.
During the third millennium BC, there developed a very intimate cultural symbiosis between the Sumerian and the Akkadian language users, which included widespread bilingualism. The influence of Sumerian on Akkadian (and vice versa) is evident in all areas, from lexical borrowing on a massive scale, to syntactic, morphological, and phonological convergence. This has prompted scholars to refer to Sumerian and Akkadian in the third millennium as a sprachbund. Akkadian gradually replaced Sumerian as the spoken language of Mesopotamia somewhere around the turn of the 3rd and the 2nd millennium BC (the exact dating being a matter of debate), but Sumerian continued to be used as a sacred, ceremonial, literary, and scientific language in Mesopotamia until the 1st century AD.
Libraries were extant in towns and temples during the Babylonian Empire. An old Sumerian proverb averred that "he who would excel in the school of the scribes must rise with the dawn." Women as well as men learned to read and write, and for the Semitic Babylonians, this involved knowledge of the extinct Sumerian language, and a complicated and extensive syllabary.
A considerable amount of Babylonian literature was translated from Sumerian originals, and the language of religion and law long continued to be the old agglutinative language of Sumer. Vocabularies, grammars, and interlinear translations were compiled for the use of students, as well as commentaries on the older texts and explanations of obscure words and phrases. The characters of the syllabary were all arranged and named, and elaborate lists were drawn up.
Many Babylonian literary works are still studied today. One of the most famous of these was the Epic of Gilgamesh, in twelve books, translated from the original Sumerian by a certain Sin-liqe-unninni, and arranged upon an astronomical principle. Each division contains the story of a single adventure in the career of Gilgamesh. The whole story is a composite product, although it is probable that some of the stories are artificially attached to the central figure.
Mesopotamian mathematics and science was based on a sexagesimal (base 60) numeral system. This is the source of the 60-minute hour, the 24-hour day, and the 360-degree circle. The Sumerian calendar was based on the seven-day week. This form of mathematics was instrumental in early map-making. The Babylonians also had theorems on how to measure the area of several shapes and solids. They measured the circumference of a circle as three times the diameter and the area as one-twelfth the square of the circumference, which would be correct if pi were fixed at 3. The volume of a cylinder was taken as the product of the area of the base and the height; however, the volume of the frustum of a cone or a square pyramid was incorrectly taken as the product of the height and half the sum of the bases. Also, there was a recent discovery in which a tablet used pi as 25/8 (3.125 instead of 3.14159~). The Babylonians are also known for the Babylonian mile, which was a measure of distance equal to about seven modern miles (11 km). This measurement for distances eventually was converted to a time-mile used for measuring the travel of the Sun, therefore, representing time.
From Sumerian times, temple priesthoods had attempted to associate current events with certain positions of the planets and stars. This continued to Assyrian times when Limmu lists were created as a year by year association of events with planetary positions, which, when they have survived to the present day, allow accurate associations of relative with absolute dating for establishing the history of Mesopotamia.
The Babylonian astronomers were very adept at mathematics and could predict eclipses and solstices. Scholars thought that everything had some purpose in astronomy. Most of these related to religion and omens. Mesopotamian astronomers worked out a 12-month calendar based on the cycles of the moon. They divided the year into two seasons: summer and winter. The origins of astronomy as well as astrology date from this time.
During the 8th and 7th centuries BC, Babylonian astronomers developed a new approach to astronomy. They began studying philosophy dealing with the ideal nature of the early universe and began employing an internal logic within their predictive planetary systems. This was an important contribution to astronomy and the philosophy of science and some scholars have thus referred to this new approach as the first scientific revolution. This new approach to astronomy was adopted and further developed in Greek and Hellenistic astronomy.
In Seleucid and Parthian times, the astronomical reports were thoroughly scientific; how much earlier their advanced knowledge and methods were developed is uncertain. The Babylonian development of methods for predicting the motions of the planets is considered to be a major episode in the history of astronomy.
The only Greek Babylonian astronomer known to have supported a heliocentric model of planetary motion was Seleucus of Seleucia (b. 190 BC). Seleucus is known from the writings of Plutarch. He supported Aristarchus of Samos' heliocentric theory where the Earth rotated around its own axis which in turn revolved around the Sun. According to Plutarch, Seleucus even proved the heliocentric system, but it is not known what arguments he used (except that he correctly theorized on tides as a result of Moon's attraction).
Babylonian astronomy served as the basis for much of Greek, classical Indian, Sassanian, Byzantine, Syrian, medieval Islamic, Central Asian, and Western European astronomy.