A grammatical case is a category of nouns and noun modifiers (determiners, adjectives, participles, and numerals) which corresponds to one or more potential grammatical functions for a nominal group in a wording. In various languages, nominal groups consisting of a noun and its modifiers belong to one of a few such categories. For instance, in English, one says I see them and they see me: the nominative pronouns I/they represent the perceiver and the accusative pronouns me/them represent the phenomenon perceived. Here, nominative and accusative are cases, that is, categories of pronouns corresponding to the functions they have in representation.
English has largely lost its inflected case system but personal pronouns still have three cases, which are simplified forms of the nominative, accusative (including functions formerly handled by the dative) and genitive cases. They are used with personal pronouns: subjective case (I, you, he, she, it, we, they, who, whoever), objective case (me, you, him, her, it, us, them, whom, whomever) and possessive case (my, mine; your, yours; his; her, hers; its; our, ours; their, theirs; whose; whosever). Forms such as I, he and we are used for the subject ("I kicked the ball"), and forms such as me, him and us are used for the object ("John kicked me").
As a language evolves, cases can merge (for instance, in Ancient Greek, the locative case merged with the dative), a phenomenon known as syncretism.
Languages such as Sanskrit, Kannada, Latin, Tamil, and Russian have extensive case systems, with nouns, pronouns, adjectives, and determiners all inflecting (usually by means of different suffixes) to indicate their case. The number of cases differs between languages: Persian has two; modern English has three but for pronouns only; Torlakian dialects, Classical and Modern Standard Arabic have three; German, Icelandic, Modern Greek, and Irish have four; Romanian and Ancient Greek have five; Bengali, Latin, Russian, Slovak, Kajkavian, Slovenian, and Turkish each have at least six; Armenian, Czech, Georgian, Latvian, Lithuanian, Polish, Serbian, Croatian and Ukrainian have seven; Mongolian, Marathi, Sanskrit, Kannada, Tamil, Telugu, Malayalam, Assamese and Greenlandic have eight; Old Nubian had nine; Basque has 13; Estonian has 14; Finnish has 15; Hungarian has 18; and Tsez has at least 36 cases.