The Cases in English
As in Latin, so in English "case" refers to a change in the form of a word which indicates how that word is used in a sentence, that is, how it relates syntactically to other words in the sentence. In English, the only words that are marked formally are pronouns and the "declension" of pronouns shows three cases: The subject case, the object case, and the possessive case. Examples: "I, me, my/mine" and "he, him, his." Other words distinguish their syntactic usage within a sentence by their word position. Examples: "Man bites Dog" and "Henry gave Sam Mary."
Nevertheless, English Cases are often taught by their Latin names. It is agreed that there is no "Ablative" in English (although there is an "Instrumental Case") but English grammars often keep the Dative in addition to the Accusative, thereby creating the following four cases: Nominative, Genitive, Dative, Accusative. However, the Dative case is really indistinguishable from the accusative case: "I gave him the book" ("him" is Dative) or "I saw him." ("him" is Accusative). (See how the loss of a distinct dative affects English verbs.) As a result, it seems to us more accurate to speak of the cases in English as: subject, object (including direct object, indirect object, and object of the preposition), and possessive cases.
The subject is the person or thing about which a statement is made. If the verb that makes the statement (the predicate) is active, then the subject (the subject of the verb) is the person or thing that is doing something: "He came. He saw. He conquered." If the verb that makes the statement is passive, then the subject is the person or thing that is affected by the action: "The Helvetii were conquered by Caesar; Caesar was killed by Brutus."
In English, the object case is primarily used to express three syntactical relationships: 1. direct object, 2. indirect object, and 3. object of prepositions. In Latin these functions are expressed by 1. the Accusative Case, 2. the Dative Case and 3. the Ablative or Accusative case (depending on the preposition).
The direct object is the person or thing directly affected by the action of an active verb. "He drove the car." The action is "driving" and the thing directly affected is "the car." NOTE: Whenever a verb has a direct object it is called a transitive verb. Not all verbs are transitive, however. Consider the following: "I run quickly." Here, running is an activity by itself; it does not affect any other person or thing. The verb is intransitive. Intransitive verbs do not have direct objects. However, the same verb with a different meaning can be transitive: "I run the store when my father is away." Since "run" now has a direct object, it is considered a transitive verb. Here is another example: "I gave away the book." Here, "the book" is directly affected by the giving and so it is the direct object. In Latin, the direct object is always put in the accusative case.
Readers of Latin distinguish the direct object from the indirect object. The indirect object is the person or thing indirectly affected by the action of the verb. Consider a variation on the last sentence above: "I gave him the book." (Or, the same thing: "I gave the book to him.") "The book" is still the direct object (directly affected by the "giving"), but we have added a person indirectly affected by the giving: "him." "Him" is the indirect object. In this case, it is the beneficiary of the giving. Suppose on the other hand, the person indirectly affected was hurt by the action: "I gave him the finger." Here we have the indirect object used to describe the person disadvantaged by the giving. In Latin, the indirect object is always put into the dative case, but the Latin Dative Case has greater flexibility and more functions than the indirect object function in English.
The possessive case only really exists in English in the personal pronouns: my, mine; your, yours; his, her, hers, its; our, ours, your, yours, and their, theirs. These are truly inflected possessive forms. Elsewhere we use "apostrophe s" ['s] to mark the "possessive case." Historically this is just a contraction of "his" as in "Shakespeare his wife was born in Stratford" becoming "Shakespeare's wife...." In English this case is used almost exclusively for possession: "my book" or "his house"; or for relationships that are like possession: "our lesson" and "their god." One should be careful, however, not to think that the possessive case only indicates material or legal possession. Originally it was as flexible as the genitive case in Latin, and as a result may still in English indicate relationships that are more subtle or complex than ownership. Consider: "my mother" ... surely, I don't own her in any literal way. Similarly, "my love" or "my friend." These are not "ownership" relationships (or so we hope -- as always, grammar is not precise about content). The potential complexity of these "possessive" relationships may become clear if you consider that the alternative form for "possession" in English uses the preposition "of" -- "the country of the Helvetii" or "the leader of the Catholics." This preposition is actually very similar to the Latin genitive case in the way that it can express a number of different types of relationships. Here are a few to think about: The Driver of the Bus; The love of God; My love of God; Rivers of milk and honey.