Editing Linguistics (section)

== Case Systems ==
Case systems organize how nouns and their related words (pronouns, adjectives) connect to verbs and other sentence elements, indicating their grammatical roles (such as subject, object, et cetera). '''Transitive''' and '''intransitive''' verbs are categories that describe how verbs interact with objects within sentences. The distinction between them is foundational in understanding sentence structure and grammar across languages. 

Transitive verbs require one or more '''objects''' to complete their meaning; they express <u>actions</u> that are done <u>to</u> someone or something. The object of a transitive verb receives the action of the verb. In the sentence "She reads a book," "reads" is a transitive verb because the action is being performed on an object, "a book." 

Intransitive verbs are verbs that do not take an object; their meaning is complete without needing to express an action being performed on someone or something. Intransitive verbs often describe actions, states of being, or occurrences that involve only the subject. In the sentence "He sleeps," "sleeps" is an intransitive verb because there is no object receiving the action; the verb simply describes the subject's state or action.

Some verbs can be both transitive and intransitive, depending on their use in a sentence; they are known as '''ambitransitive''' verbs. For example, "to eat" can be used transitively as in "She eats an apple" or intransitively as in "She eats quickly." While transitive verbs require direct objects to complete their meaning, some intransitive verbs can be followed by other types of '''complements''' (like adverbials or prepositional phrases) that provide additional information but do not receive the action of the verb.

A subtype of transitive verbs, '''ditransitive''' verbs, require <u>two</u> objects (direct ''and'' indirect) to complete their meaning, as in "She gave her friend a gift," where "gave" is the ditransitive verb, "her friend" is the indirect object, and "a gift" is the direct object.

=== Nominative-Accusative ===
In these language systems, the <u>subject</u> of both transitive and intransitive verbs is marked by the <u>nominative case</u>, and the <u>object</u> of transitive verbs is marked by the <u>accusative case</u>. This alignment emphasizes the action's '''agent''', regardless of the verb's '''transitivity'''. This system is the most common type of alignment; many <u>Indo-European</u> languages, such as <u>English</u>, <u>Spanish</u>, and <u>Russian</u>, primarily use nominative-accusative alignment, although in <u>English</u>, case marking is largely restricted to personal pronouns ("I" versus "me").

=== Ergative-Absolutive ===
These languages mark the subject of an intransitive verb in the same way as the <u>object</u> of a transitive verb - both in what's called the '''absolutive''' '''case''' - while the <u>subject</u> of a transitive verb is marked differently, in the '''ergative case'''. This alignment emphasizes the action's undergoer or the participant most directly affected by the action. Languages such as <u>Basque</u>, <u>Georgian</u>, and many <u>Australian Aboriginal</u> languages exhibit ergative-absolutive alignment.

=== Split Ergativity ===
A system where both '''nominative-accusative''' and '''ergative-absolutive''' alignments are used, under different conditions. These conditions can be based on grammatical factors such as tense, aspect, or the person of the subject, or on semantic factors like the nature of the verb or its participants. Languages with split ergativity include <u>Georgian</u>, where the split is based on the verb's tense or aspect, and <u>Hindi-Urdu</u>, which shows ergative behavior in perfective aspects of certain verbs.

=== Tripartite ===
Where the subject of an intransitive verb, the subject of a transitive verb, and the object of a transitive verb each receive different '''case markings'''. This is relatively rare among the world's languages, as it requires a clear and distinct marking for each of these roles:

* <u>Nominative case</u> marks the subject of intransitive verbs.
* <u>Accusative case</u> marks the object of transitive verbs.
* <u>Ergative case</u> marks the subject of transitive verbs.

This system provides a clear distinction between subjects acting upon objects and subjects acting alone. An example of a language with a tripartite alignment is <u>Nez Perce</u>, spoken in the Pacific Northwest of the United States.

=== Active-Stative ===
Languages of this system categorize <u>subjects</u> based on whether they are '''agents''' (performers of an action) or '''patients''' (recipients of an action). Unlike nominative-accusative or ergative-absolutive systems that categorize based on transitivity, active-stative systems allow the verb's subject to be marked differently based on semantic roles, even in intransitive sentences.

In '''Split-S''' languages there is a consistent rule for marking subjects of intransitive verbs as either agents or patients, based on the verb or the verb's semantics. In '''Fluid-S''' languages, the marking depends on the verb's semantics or the speaker's perspective. A verb like "to run" might mark its subject as an agent in one context but as a patient in another, depending on whether the running is '''volitional'''. 

=== Direct-Inverse ===
This system typifies some indigenous languages of the <u>Americas</u>, and marks the direction of the action in terms of the '''hierarchy of participants''' (often based on animacy or topicality). A '''direct''' marking indicates that the action follows the <u>expected hierarchy</u> (a higher-ranking agent acting on a lower-ranking patient), while an i'''nverse''' marking shows that the action goes <u>against</u> the expected hierarchy.

=== Differential Object Marking (DOM) ===
DOM is a related phenomenon where the <u>object</u> of a verb is marked differently based on specific semantic or pragmatic factors, such as definiteness, animacy, or specificity. This can sometimes blur the lines with '''accusative''' systems but serves different functions by highlighting certain features of the direct object.

=== Austronesian Alignment ===
This system, found in many <u>Austronesian</u> languages, features a unique way of marking the focus of a sentence through '''voice''' or '''trigger'''. Rather than focusing on the agent or patient inherently, the language can <u>mark</u> which participant is the focus of a given clause, affecting verb morphology.

=== Semantic Role-Based ===
Some languages employ case marking systems that are more directly tied to the '''semantic roles''' of participants, such as <u>experiencer</u>, <u>benefactive</u>, or <u>instrument</u>, rather than or in addition to their '''syntactic roles'''. 

=== Fusion between Systems ===
Some languages exhibit features of more than one alignment system, demonstrating the fluidity of case roles and grammatical structures across languages. Case systems can change over time within a language, contributing to the development of mixed or evolving alignments. Historical linguistics often studies these changes to understand language evolution. The '''functional load''' of case markings can vary widely, with some languages relying heavily on case to indicate grammatical relations and others using word order or auxiliary words for the same purpose.