Comitative case

The comitative case (abbreviated COM) is a grammatical case that denotes accompaniment. In English, the preposition "with," in the sense of "in company with" or "together with," plays a substantially similar role (other uses of "with," like in the meaning of "using" or "by means of" (I cut bread with a knife), correspond to the instrumental case or related cases).

Comitative case encodes a relationship of "accompaniment" between two participants in an event, called the "accompanee" and the "companion." In addition, there is a "relator" (which can be of multiple lexical categories, but is most commonly an affix or adposition). Use of Comitative case gives prominence to the accompanee. This Italian sentence is an example:

In this case, il professore is the accompanee, i suoi studenti is the companion, and con is the relator. As the accompanee, il professore is the most prominent.

Animacy also plays a major role in most languages with a comitative case. One group of languages requires both the accompanee and the companion to be either human or animate. Another group requires both to be in the same category: both human or both animate. A third group requires an animate accompanee and an inanimate companion. Other languages have no restrictions based on animacy.

The comitative case is often conflated or confused with other similar cases, especially the instrumental case and the associative case.

The comitative relates to an accompanee and a companion, and the instrumental relates to an agent, an object, and a patient. Enrique Palancar defines the role of Instrumental case as 'the role played by the object the Agent manipulates to achieve a change of state of the Patient.' Even though the difference is straightforward, because the instrumental and the comitative are expressed the same way in many languages, including English, it is often difficult to separate them.

Russian is one of many languages that differentiates morphologically between instrumental and comitative:

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