How are the relative pronoun, interrogative pronoun, and the interrogative adjective similar and different in declension, translation, and use?
Relative pronouns are often seen in clauses. The most common relative pronouns are that, which, whose, whom, who.
Interrogative pronouns are often used to suggest questions, hence the keyword "interrogative." The interrogative pronouns are what, which, whose, whom, who.
Interrogative adjectives are used to modify nouns and pronouns in questions. The interrogative adjectives are what, which, whose.
Declension (Variation): These pronouns are used to best fit the noun in the sentence. If we are talking about a human being, we will use whose, whom, who. If we are talking about things, we may use that, which. Relative pronouns and interrogative pronouns are both used to replace nouns because they are pronouns; however, relative pronouns are usually in statements and interrogative pronouns are used in questions. Interrogative adjectives can modify either of these as long as a the proper pronoun replaces the proper noun.
Translation: Old English has seen many of these words when demonstrative adjectives were introduced as well.
Use: Relative pronouns are mostly used in dependent clauses. Interrogative pronouns and adjectives are mostly seen in questions. They are buzzwords to identify a question.