Personal Pronouns may be divided into Subject Pronouns and Object Pronouns.
Note: yo = I, tú = you (informal), usted (Ud.) = you (formal), él = he, ella = she, nosotros = we (males/mixed group), nosotras = we (females), vosotros = you guys (informal, males/mixed group), vosotras = you guys (informal, females), ellos = they (males/mixed group), ellas = they(females), ustedes (Uds.) = you all (formal)
Spanish Subject Pronouns are used in a similar way as in English. Exception: These pronouns do not need to be expressed since the verb itself will identify the subject. In the examples below the subject pronoun is omitted without changing the meaning:
Yo quiero comer. - I want to eat. Quiero comer. - I want to eat.
Tú quieres salir. - You want to leave. Quieres salir. - You want to leave.
El quiere dormir. - He wants to sleep. Quiere dormir. - He wants to sleep.
Ellos quieren escribir. - They want to write. Quieren escribir. - They want to write.
Usually, the subject pronoun is omitted when no emphasis is required and where no ambiguity is possible, as:
Compro las telas.
I buy the cloths.
Saca las cuentas y firma las cartas.
He draws the bills and signs the letters.
Ha tenido una entrevista con su abogado.
She has had an interview with her lawyer.
The subject pronoun is used to create emphasis, as:
Yo he comprado el yate y no usted. I have bought the yacht and not you.