Editing Nominative–accusative alignment (section)

===Split ergativity===
It is common for languages (such as [[Georgian language|Georgian]] and [[Hindustani grammar|Hindustani]]) to have overlapping alignment systems, which exhibit both nominative–accusative and ergative–absolutive coding, a phenomenon called [[split ergativity]]. In fact, there are relatively few languages that exhibit only ergative–absolutive alignment (called pure ergativity) and tend to be isolated in certain regions of the world, such as the [[Caucasus]], parts of [[North America]] and [[Mesoamerica]], the [[Tibetan Plateau]], and [[Australia]]. Such languages include [[Sumerian language|Sumerian]], [[Standard Tibetan]], and [[Mayan language|Mayan]].<ref>{{cite book|title=An Introduction to Syntax|url=https://archive.org/details/introductiontosy0000vanv|url-access=registration|first1=Robert D.|last1= Van Valin|publisher=Cambridge University Press|year= 2001|isbn=9780521635660}}</ref>