Fillmore[Charles Fillmore, The case for case, 1968.] proposed a theory of deep case structures, in which elements of a sentence are related to the verb by deep case[ case: an inflectional form of a noun, pronoun, or adjective indicating its grammatical relation to other words; such a relation whether indicated by inflection or not. -- Webster's 9th New Collegiate Dictionary] relationships.
Unlike some languages, English does not modify most words for different cases. Cases used in English are:
| Formal Name: | Description: | Example: | Example Use: |
| Nominative | subject | he | He hit the ball. |
| Objective | direct object | him | John hit him. |
| Dative | indirect object | him | I gave him a book. |
| Genitive | possessive | his | He lost his keys. |
Although English does not make the cases obvious, Fillmore argued that the cases are still present in English:
in
| Mother baked for three hours. | |
| The pie baked for three hours. | |
| * | Mother and the pie baked for three hours. |
Why is the third sentence anomalous?[Linguists use the * marker to indicate a bad sentence.] Although both ``Mother'' and ``the pie'' are syntactic subjects, Fillmore argued that they are in different deep cases and thus cannot be conjoined.