Sumerian ceases to be a mother tongue

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Sumerian appears to have stopped being transmitted as a first language during the early second millennium BCE, displaced by Akkadian, while continuing for well over a thousand years afterwards as a language of liturgy, scholarship and scribal training — the reason so much of it is recoverable, since Akkadian-speaking scribes compiled bilingual lexical lists to teach it. The date of the transition is inferred from the textual record and is debated among Assyriologists; it is given here as a period rather than a year.

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