The equative case (abbreviated EQU) is a grammatical case prototypically expressing the standard of comparison of equal values ("as… as…"). The equative case has been used in very few languages in history.[citation needed] It was used in the Sumerian language, where it also took on the semantic functions of the essive case ("in the capacity of…") and similative case ("like a…").[1]
In Sumerian, the equative was formed by adding the suffix -gin7 to a noun phrase, for example:
lugal
"king"
→
lugal-gin7
"king-like", "like a king"
lugal → lugal-gin7
"king" {} {"king-like", "like a king"}
nitah-kalaga
"mighty man"
nitah-kalaga-gin7
"like a mighty man"
nitah-kalaga → nitah-kalaga-gin7
{"mighty man"} {} {"like a mighty man"}
In Ossetic, it is formed by adding the suffix -ау [aw]:[2]
фӕт
"arrow"
фӕтау
"arrowlike"
фӕт → фӕтау
"arrow" {} "arrowlike"
Ницы
фенӕгау
йӕхи
акодта
Ницы фенӕгау йӕхи акодта
lit. "nothingseer-like himself made" ("[he or she] pretended to see nothing").
The equative case is also found subdialectally in the Khalkha dialect of Mongolian, where it can be formed by adding the suffixes -цаа [tsaa], -цоо [tsoo], -цээ [tsee] or -цөө [tsöö], depending on the vowel harmony of the noun. It is rare and highly specialized, used exclusively to denote the height or level of an object:[3]
эрэг
"[river]bank"
эрэгцээ
"as high as the bank"
эрэг → эрэгцээ
"[river]bank" {} {"as high as the bank"}
өвдөг
"knee(s)"
өвдөгцөө
"up to the height of the knee(s)"
өвдөг → өвдөгцөө
"knee(s)" {} {"up to the height of the knee(s)"}
In Archi, a Northeast Caucasian language, the equative case is indicated by the case marker -qʼdi:[4]
misgin-ni-qʼdi
poor-OBL-EQU
"In the way of the poor."
It is also found in the Turkic Khalaj language and in languages from South America such as Quechua, Aymara, Uro and Cholón.[citation needed]
Sireniki Eskimo had an equative (or comparative) case for describing similarities between nouns.[5]