In general, case or case-marking is a morphosyntactic device or mechanism that is used to indicate, at a minimum, who is doing what to whom. English, for example, often uses word order to show which noun is the entity that is performing the action of the verb and which noun is affected by the action of the verb.

(1) Mary gave the comic book to Sue.

In (1), a traditional description of the case-marking involved would label "Mary" as the subject (see this wikipedia article on grammatical subject) of the sentence, "the comic book" as the direct object (see this wikipedia article on direct object), and "Sue" as the indirect object. Other languages, including all of the languages that were written in cuneiform, do not primarily use word order to indicate who is doing what to whom.

'The king built the temple for Inanna'

In the Sumerian clause in (2), however, the primary mechanism for indicating who is doing what to whom is the use of case-marking postpositions such as the dative postposition /-ra/ and the ergative postposition /-e/. The absence of any postposition is associated with the absolutive-nominative case.

Sumerian makes use of both nominal postpositions and verbal infixes to code the information that is generally subsumed under case-marking. Nominal case-marking postpositions are dealt with on this page, but the verbal elements that participate in case-marking are organized on two separate pages: a verbal agreement page that deals with the verbal elements corresponding to the core or grammatical cases below, and a dimensional infix page that covers the verbal infixes that are typically associated with the adverbial cases listed below.

Although the morphological element in Sumerian that assign cases to nominal phrases are often spoken of simply as cases, case markers, or suffixes, their phonological behavior as well as the fact that a single element can qualify a complicated string of appositions that consists of several nominal phrases suggests that they are postpositions rather than the kind of desinences or suffixes seen in well-known languages such as Latin or Arabic.

Like other languages that make use of a large number of nominal case markers such as Finnish or Turkish, two subsets of case-marking postpositions can be identified: a relatively small number of core, grammatical, or structural cases and a much larger number of adverbial or inherent cases that perform many of the same functions that prepositions do in a language like English.

There are three nominal cases that should probably be categorized as core or grammatical in nature: the zero-marked absolutive/nominative case, the ergative case-marking postposition /*-e/, which is formally identical with the locative-terminative case-marking postposition, and the genitive case-marking postposition /*-a/.

Others would exclude the genitive case from the core/grammatical set and include it among the adverbial cases listed below. It is somewhat unclear how ergative case-marking is currently being evaluated in the generative tradition, but structural case would presumably only be available to the unmarked nominative case with both ergative and genitive relegated to the adverbial set.

There are at least seven and possibly eight adverbial cases that can be distinguished on purely formal grounds, and these can be divided into two groups on the basis the vowel that occurs in the full form of each postposition. One subseries has /e/ (and, perhaps /i/ in /-gin/) as its characteristic vowel.

Traditional grammars of Sumerian do not, as a rule, attempt to distinguish classes of postpositional elements; each postposition is treated as a separate entity and only associated with one or more verbal agreement or dimensional infix morphemes. The locative-terminative postposition is formally identical to both the ergative postposition and also, in recent work, an inanimate dative (Zólyomi 1999, 216 and 251-253). The differentiation of these three functions is largely dependent on particular theories of grammar, although nearly all theories differentiate the ergative and the locative-terminative. The allative, known in the older literature as the terminative case, is usually associated with the *-ši- verbal infix. The adverbiative, which was proposed by Attinger (1993, 253), may or may not be identical in form with the allative.

The four remaining adverbial postpositions include /a/ as the characteristic vowel.

The locative is often associated with the *-ni- verbal infix, or alternatively with the *-a- verbal infix. The precise mechanism underlying the co-occurrence of the locative postposition with one or both of these verbal infixes remains highly controversial in the literature, see in particular the standard theory, Gragg's model as well as the directive case hypothesis. The ablative is generally associated with the *-ta- verbal infix as well as the *-ra verbal infix. The comitative regularly co-occurs with the *-da verbal infix. The dative is the only postposition which shows an animacy/gender oppositions within both the postpositional series (-ra only modifies animate nouns, whereas the inanimate dative is indicated by the locative-terminative postposition) and the verbal infixes, where a full inflection of the dative infix for person and Gender is usually reconstructed.

• [http://en.wikipedia.org/wiki/Morphosyntactic_alignment Wikipedia: Morphosyntactic Alignment]
• [http://www.sil.org/linguistics/GlossaryOfLinguisticTerms/WhatIsCase.htm Summer Institute of Linguistics: Case]

• Attinger, Pascal. 1993. Eléments de linguistique sumérienne: La construction de du11/e/di "dire". Göttinger: Vandenhoeck & Ruprecht. [Synthetic treatments of both nominal postpositions and the verbal morphemes that are generally thought to agree with them are presented in detail with useful descriptions of orthographic variations and full bibliographies, pp. 211-260.]
• Balke, Thomas. 1999. Kasus in Sumerischen. Sprachtypologie und Universalienforschung 52: 118-129.
• Thomsen, Marie-Louise. 2001. The Sumerian Language: An Introduction to its History and Grammatical Structure. 3d ed. with Supplementary Bibliography (pp. 364-376). Mesopotamia: Copenhagen Studies in Assyriology 10. Copenhagen: Akademisk Forlag. [The standard English-language reference grammar of Sumerian, first published in 1984 and minimally revised in the intervening years; nominal cases are dealt with in pp. 88-109, §§156-220.]
• Wilcke, Claus. 1990. Orthographie, Grammatik und literarische Form: Beobacktungen zu der Vaseninschrift Lugalzaggesis (SAKI 152-156). In Tzvi Abusch, John Huehnergard and Piotr Steinkeller, eds., Lingering Over Words: Studies in Ancient Near Eastern Literature in Honor of William L. Moran. Harvard Semitic Studies 37. [pp. 455-504, in particular pp. 459-464 and 471-476.]