Very simply, a prepositional pronoun is the specific type of pronoun required if it is the object of a preposition. Prepositions are parts of speech which initiate a phrase that expresses a relationship between two words. In the English language, about, above and across are just three among roughly one hundred prepositions. All prepositional phrases must contain a noun that is the object of the preposition. When that noun is a pronoun, it is called a prepositional pronoun.
In the sentence, “She kissed him on the cheek,” the word on is a preposition. The noun cheek is the object of that preposition, connecting it to the verb “kissed.” The relational question addressed is: where she kissed. Prepositions are versatile words present in possibly every language of the world. Relationships described by such words as “with” and “for” are critical in describing the human social experience.
A pronoun is a generic substitute word used in place of a noun. Presumably, the woman in the preceding paragraph’s example sentence has a proper name, and the pronoun she takes its place. The same is true of the pronoun him. Both refer to people, and are therefore called personal pronouns. They also represent the two specific types of personal pronouns in the English language — the subjective and objective.
“She kissed him on the cheek.” She is the subject of the sentence. “He” is the object of verb “kissed,” and the pronoun must therefore be changed to its objective form him. The personal pronouns are “I” for first person, “you” for second person, and “he” for third person. Plural pronouns exist for each case, such as “we” for first person, and pronouns distinguished by gender are common in many languages of the world.
All of the pronouns above have their objective form, such as “us” for the first person plural. In English, the objective pronoun is the identical form for the prepositional pronoun. “She danced with him.” Insofar as him is the object of the preposition with, this prepositional pronoun must take the objective form. In addition to the personal pronouns, there is one unique interrogative pronoun — who — which also has an objective form — whom.
Unlike English, there are other languages which have many multiple forms of pronouns dependent on their grammatical use. This may include a separate form for being the direct object of a verb, or the object of a preposition. Spanish and Portuguese are two examples. Some languages, such as Arabic, employ inflected prepositions, essentially contracting a preposition and combining it with the prepositional pronoun into a single compound word. Other languages may even have entirely different forms of the same pronoun when it is the object of some of the more common prepositions such as from, in and with.