

In Arabic, if the relative pronoun is referring back to a noun that is a direct object or the object of a preposition (like "the book I read," "the girl I wrote to"), a pronoun suffix referring to this noun must be added to the relative pronoun. Relative pronouns (such as "that, which, who") begin relative clauses, which act like adjectives and describe the noun they follow. * هتان is used with nouns in the nominative case ( المرفوع) هتين is used with nouns in the genitive and accusative cases ( المجرور والمنصوب). * هذان is used with nouns in the nominative case ( المرفوع) هذين is used with nouns in the genitive and accusative cases ( المجرور والمنصوب). * Note that all plural non-human nouns are grammatially treated as feminine, and this applies to demonstrative pronouns (as well as other things like adjectives).

Here are all the demonstrative pronouns in Arabic:
