Prolative case

In grammar, the prolative case (abbreviated PROL), also called the vialis case (abbreviated VIA), prosecutive case (abbreviated PROS), traversal case, mediative case, or translative case,^[1] is a grammatical case of a noun or pronoun that has the basic meaning of "by way of" or "via".

In Finnish, the prolative case follows an established application in a number of fossilized expressions to indicate "by (medium of transaction)".^[2] It can be used in other constructions, but then it does not sound "natural".^[3] Examples would be "postitse" ("by post"), "puhelimitse" ("by telephone"), "meritse" ("by sea"), "netitse" ("over the Internet"). A number of Finnish grammarians classify the prolative form as an adverb because it does not require agreement with adjectives like other Finnish cases.^[4] This claim is not true, however, because an adjective will agree with the prolative: "Hän hoiti asian pitkitse kirjeitse" ("He/she dealt with the matter by way of a long letter").

The prolative exists in a similar state in the Estonian language.

The vialis case in Eskimo–Aleut languages has a similar interpretation, used to express movement using a surface or way. For example, in the Greenlandic language umiarsuakkut 'by ship'^[5] or in Central Alaskan Yup'ik kuigkun 'by river' or ikamrakun 'by sled'.

Basque grammars frequently list the nortzat / nortako case (suffix -tzat or -tako) as "prolative" (prolatiboa).^[6] However, the meaning of this case is unrelated to the one just described above for other languages and alternatively has been called "essive / translative",^[7] as it means "for [something else], as (being) [something else]"; e.g., hiltzat eman "to give up for dead", lelotzat hartu zuten "they took him for a fool".^[8] The meaning "by way of" of the case labelled prolative in the above languages is expressed in Basque by means of the instrumental (suffix -[e]z).

This case is also called the prosecutive case in some languages.^[1] It is found under this name in Tundra Nenets,^[9] in Old Basque and, with spatial nouns, in Mongolian.^[10]