It is possible that you have gone through many years of schooling without knowing that nouns have “cases.” You may think “case” means a container or a unit of counting (like “24 to a case”) or a mystery project of someone like Sherlock Holmes. All that is true; but it also means an instance of something (as in “In any case, you should call home.”).
In grammar, “case” means the form of a noun, pronoun or adjective that indicates its functional relationship to other words in the sentence. In many languages other than English, the “case” of a noun is indicated by a special form — usually an ending, called more generically “an inflection.” (Verbs have inflections, too; however, they do not have “cases.”)
English shed most of its inflections some time ago, so we do not use special forms to indicate how a noun or adjective is used in a sentence. We need to pick up this information in other ways, by word order and context. Some pronouns, on the other hand, are still inflected. See Keeping Subjects and Objects in Line.
Even though English has few inflections for nouns, adjectives and pronouns, it still uses “cases.” Most of the other languages originating in Europe do, too. The source of this approach to language traces back to ancient Greece. When Latin evolved, it adopted the cases used in Greek. Hundreds of years later, Latin became the mother of the modern romance languages, and a grammatical model for German (thanks to Luther’s adoption of Latin as a grammatical template for the translation of the Latin bible into German).
English has a double inheritance from Latin: (a) directly (as the written language of medieval times), and (b) from Norman French (via the Norman invasion of 1066). The third major ancestor of English, Anglo-Saxon, came to England long before German received the “civilizing” influence of imported Latin grammar. This may explain why English evolved to be so noninflected, as compared with the tongues of its continental neighbors.
Though most English words are noninflected, their functions in an English sentence do reflect their cases. Here is a recapitulation of the cases used in classical times, which remain valid for analyzing modern English usage. Remember, this subject applies only to nouns, pronouns and adjectives.
Nominative – Used for the subject of a sentence or clause, and also for its adjectives. Also used for “predicate nouns” and “predicate adjectives,” which follow a state-of-being verb (Examples: “to be,” “to seem,” “to feel”). Predicate nouns and adjectives equate to or describe the subject of the sentence. (Don’t call this the “subjective case”; “subjective” will be understood as something else entirely.)
Possessive (Genitive) – Used to describe possession, ownership or close association (as a personal trait, for example). In English we have possessive pronouns, which are in the genitive, technically speaking. The apostrophe-s for nouns is also a genitive inflection. Often, however, we just use a prepositional phrase, with “of” (Example: “Necessity is the mother of invention.”)
Important: Do not use the apostrophe-s with pronouns! They are already in the genitive case, and need no further inflection! “It’s” is a contraction of “it is”; “its” (without the apostrophe) is the possessive pronoun. And, while we’re on the subject: Do not use apostrophes to make nouns plural! The shamefully careless or ignorant might post a sign that says, for example, “Television’s for sale.” Don’t use a genitive inflection in the place of a common plural, please!
Objective (Accusative) – Used for the direct objects of verbs and the objects of prepositions. Example: “Give me liberty or give me death!” “Liberty” and “death” in Patrick Henry’s famous oratory are in the accusative case. We cannot discern this by looking at the words (as there are no inflections), but we do know it from their functional relationship to the other words in the sentence, particularly, the verb “give.”
Dative – Used for indirect objects of verbs. Example: In the imperative sentence “Call me a cab,” the “me” is an indirect object. Were it a direct object, the response would be, “OK, you’re a cab!” Often, the dative is expressed in a prepositional phrase with “to”: Instead of saying, “Give me it!” we say “Give it to me!”
Three other cases existed in ancient days, but they did not survive the transition to modern times: The vocative, used when addressing someone, the locative, used when referring to a place or location, and the ablative, used mainly to express separation, source, cause, or means. The most famous vocative is “Et tu Brute?” The phrase was quoted by Shakespeare in his play, Julius Caesar. The “–e” ending on “Brutus” is the vocative inflection. The locative and ablative are not necessary in English because we use prepositional phrases to articulate the concepts that they expressed.