Sumerian was the first language to be written with a cuneiform or "wedge-shaped" script, which was later also used for Akkadian. This script was even adapted to Indo-European languages like Hittite (which also had a hieroglyphic script, as did the Egyptians and the Mayans) and Old Persian.
The language is agglutinative, as opposed to modern isolating languages like Chinese, in which word parts appear separated. Sumerian made heavy use of compounding; ki and dingir (land and god) come together to form the native name for Shumer, Ki-engir. Similarly, the words for big and man are compounded for the Sumerian word for king, lugal.