The term "Sumerian" is the common name given to the ancient inhabitants of southern Mesopotamia (modern day Iraq), Sumer, by their successors, the Semitic Akkadians.
The Sumerian city states rose to power during the prehistorical Ubaid and Uruk periods. Sumerian history reaches back to the 26th century BC and before, but the historical record remains obscure until the Early Dynastic III period, ca. the 23rd century BC, when a now deciphered syllabary writing system was developed, which has allowed archaeologists to read contemporary records and inscriptions. Classical Sumer ends with the rise of the Akkadian Empire in the 23rd century BC. Following the Gutian period, there is a brief "Sumerian renaissance" in the 21st century, cut short in the 20th century BC by Amorite invasions. The Amorite "dynasty of Isin" persisted until ca. 1700 BC, when Mesopotamia was united under Babylonian rule.
The most important archaeological discoveries in Sumer are a large number of tablets written in Sumerian. Sumerian writing is the oldest example of writing on earth. Although pictures - that is, hieroglyphs were first used, symbols were later made to represent syllables. Triangular or wedge-shaped reeds were used to write on moist clay. This is called cuneiform (Latin, cuneus, “wedge”). A large body of hundreds of thousands of texts in the Sumerian language has survived, such as personal or business letters, receipts, lexical lists, laws, hymns, prayers, stories, daily records, and even libraries full of clay tablets. Monumental inscriptions and texts on different objects like statues or bricks are also very common. Many texts survive in multiple copies because they were repeatedly transcribed by scribes-in-training. Sumerian continued to be the language of religion and law in Mesopotamia long after Semitic speakers had become the ruling race. The Sumerian language is generally regarded as a language isolate in linguistics because it belongs to no known language family; Akkadian, by contrast belongs to the Afro-Asiatic languages. There have been many failed attempts to connect Sumerian to other language groups. It is an agglutinative language; in other words, morphemes ("units of meaning") are added together to create words, unlike analytic languages where morphemes are purely added together to create sentences.
Understanding Sumerian texts today can be problematic even for experts. Most difficult are the earliest texts, which in many cases don't give the full grammatical structure of the language.