What is the world's oldest known written language?

The world’s oldest known written language is generally identified as Sumerian.

Sumerian was used in ancient Mesopotamia, chiefly in the southern part of modern Iraq. Its earliest clearly identifiable written records date to about 3100 BC, when scribes used an early form of cuneiform on clay tablets. The first texts were mainly administrative records tracking goods, workers, and temple activity.

Sumerian is a language isolate, meaning no confirmed relationship has been established between it and any other known language family. It was eventually displaced as a spoken language by Akkadian, a Semitic language, but remained important as a scholarly, religious, legal, and literary language for centuries.

The claim needs a small qualification: even earlier proto-writing from roughly 3200 BC is difficult to interpret, and scholars debate whether it records Sumerian. Egyptian is also among the earliest written languages, so “oldest” refers to the earliest securely attested language, not necessarily the first language humans ever spoke or wrote.