"One way in which a language becomes dead is that people simply stop speaking it: some other language spreads over the area where it is spoken, and it dies without issue. This is what happened, it seems, to Sumerian: round about 1500 BC, the Sumerian language disappeared from everyday use (though it continued to be used as a liturgical language for another thousand years). The people who spoke it must have changed over to some other language, presumably Akkadian, and the reason for that change was simply that they were conquered by peoples who spoke Akkadian, which became the general currency of the area. Sumerian may have been spoken for a long time as a minority language, but Sumerian speakers would need to speak Akkadian as well, and literature and official transactions would be in Akkadian. Anybody who wanted to get on in the world would have to speak Akkadian, but no native Akkadian speaker would have any incentive to learn Sumerian. If there were intermarriages, the children would tend to speak Akkadian. In such circumstances, the number of speakers of Sumerian would gradually shrink, until finally the language disappeared."— Charles Barber, The Flux of Language, 1964.