There were many Mesopotamian languages spoken by the people and they ranged from the Akkkadian to the Semitic and Sumerian. People in ancient Mesopotamia also spoke Elamite, Eblaite and Phoenician as well. The script used was known as cuneiform and excavation unearthed revealed the use of clay tablets on which the wedge shaped writing was common.
Cuneiform was used to write several languages including English, German, French and Spanish. But the earliest known Mesopotamia language was Sumerian and similar dialects. While the Akkadian language was widely used by the people as a spoken tongue in ancient Mesopotamia.
Sumerian was used for official purposes. The predominant language was Sumerian for all kinds of literary pursuits, religious discourses and technological pursuits as well.
Sumerian and Akkadian:
Up till the neo Babylonian times, rich variants of Akkadian was in vogue. Soon Akkadian was discontinued and the language called Aramic became common for administrative purposes.
The cuneiform script was adopted in 4 BC characterized by triangular shapes which helped make impressions on soft clay. Much of the knowledge of languages prevalent during the period comes from the excavation of temples and the descriptions around them.
As the cuneiform script was difficult to master before it became a prevalent language of Mesopotamia, special people were hired for the task of writing. Mesopotamians gained literacy much later under King Sargon and archaeological excavations have shown widespread literacy during the following period. The Sumnerians and the Akkadians made literary and cultural progress and there was a lot of cross fertilization of ideas as well.
There is evidence of a large section of the population well versed in the language of Mesopotamia which was a rich mixture of Sumerian and Akkadian. At a later period, Akkadian gained prominence over the existing Sumerian as a language that was popular and spoken by a large section of the population.
The changeover happened around 2 BC and historical opinion is divided about the exact time frame when Akkadian became a widely spoken tongue in ancient Mesopotamia. Even though Akkadian was a language of everyday use by the population, Sumerian continued to be a favorite language of Mesopotamia for all kinds of ceremonies and literary pursuits till 1BC.