Linguistics
Some languages group the subject of 'she sleeps' with objects, not subjects
In English, the subject of 'she sleeps' and the subject of 'she hits him' are marked the same way. In ergative-absolutive languages like Basque, Georgian and Tibetan, the lone subject of 'she sleeps' is instead marked like the object of a transitive verb, while transitive subjects get their own special ergative case — a different answer to a question every grammar has to settle: who counts as central to a sentence.