Sumerian

Sumerian was spoken in southern Iraq in the fourth and third millennia BCE, and it is the language of the earliest substantial writing anywhere. Cuneiform was developed to write it, beginning as an accounting notation and becoming a full script capable of recording literature, law and liturgy. Sumerian has no demonstrated relative.

Proposals connecting it to Dravidian, to Uralic, to Caucasian languages and to others have been made and none has been accepted, and the reason is partly that the language is genuinely isolated and partly that the comparative method has very little to work with when one member of a proposed pair is attested only in a script that under-represents its phonology. It is also typologically unlike its neighbours: agglutinative and ergative where Akkadian, the Semitic language that shared the same cities, is neither. The two were in contact for centuries, and each borrowed heavily from the other. By around 2000 BCE Sumerian had ceased to be anybody's mother tongue, which in most cases is the end of a language's story. Here it was not. The isolation is worth holding onto for a further reason. Sumerian stands at the head of the written record for the whole ancient Near East, and much of later Mesopotamian religion, written in Akkadian, is continuous with what it first recorded. The oldest religious literature anyone can read is therefore in a language with no known relatives, and nothing in its grammar can be checked against a sister tongue.

After Sumerian stopped being spoken it went on being written for roughly two thousand years, and that makes it one of the earliest documented cases of a language kept alive by religion. Akkadian-speaking scribes learned it in school, copied its literature, and compiled bilingual lists and grammars to teach it, in a curriculum that is itself the reason so much survives. Temple liturgy in particular stayed Sumerian: laments of the kind performed by the gala priests, hymns to the gods of the great cities, and incantations were composed and recited in it long after nobody outside the scribal and priestly classes could understand a word.

The pattern is familiar from later cases, Latin in the western church, Ge'ez in Ethiopia, Sanskrit in temple ritual, Old Church Slavonic in Orthodox liturgy, Coptic in Egypt, and this is the earliest instance anyone can document. What it preserved is substantial: the hymn cycle attributed to Enheduanna, the laments over the destroyed cities, and a body of myth about Inanna, Enki and Enlil that is the oldest religious literature in existence. A language with no relatives and no speakers left the deepest single deposit of religious text in the ancient world, because a priesthood would not let it go.