A personal pronoun is used to refer to the person speaking, the person spoken to or the person spoken about. In contrast with all other types of pronouns personal pronouns possess the grammatical morphological Categories of Person, Number, Case (Nominative I, Possessive /conjoint form/ my, Objective me, Absolute /absolute form/ mine)
The pronouns in the nominative Case form function as a subject, the pronouns in the possessive case form function as adjectives, the pronouns in the objective Case form function accordingly as objects, while the pronouns in the Absolute form function as a nominative group (This book is mine = my book – these forms are always accented in speech and prosodically brought out).
Reflexive pronouns embrace indefinite oneself, thus slightly extending the membership: myself, yourself, himself, herself, itself, oneself, ourselves, yourselves, themselves. They possess a category of number, and sometimes when a mixture of persons is involved the reflexive pronoun conforms to 1st person, or to 2nd person (expressed in a subject): You, John and I mustn’t deceive ourselves. You and John mustn’t deceive yourselves. One mustn’t fool oneself)
Relative pronouns possess the categorial distinctions of gender (inanimate or animate in the antecedent), and case:
1. who, whom, whose: I met a friend who was at school with you.
2. which, whose: A war broke out which lasted forty years.
That is a relative pronoun of a more general semantics: The letter that came this morning was from my father. The woman that spoke to me in the bus used to live near me in Exeter. All that I have is yours. It was only much later that I started to feel better.