An Overview of Subject Pronouns:

Subject pronouns usually precede the verb and indicate who is responsible for the action described by the verb. For example, yo hablo, tú comes, ella escribe. In general, a subject pronoun answers the question "who?" in relation to the verb (the agent of the verbal action). For example, we know that yo is a subject pronoun in the sentence Yo estudio historia because it answers the question ¿Quién estudia historia?

Spanish has the following subject pronouns, illustrated in the table with common verbs in the present tense. Take note of how the verbs agree in person, number, and sometimes gender with the subject pronouns:

Let's consider each of the subject pronouns and learn how they are formed and used:

yo: This is the 1st person singular subject pronoun (that's the person who is writing or talking). The verb's ending must agree with yo. In the present tense, the verb should end in -o in order to agree with yo, e.g.: Yo bailo y bebo por la noche. Remember to write yo with a lower case "y" unless it is at the beginning of a sentence (unlike in English which always capitalizes "I").

tú: This is the 2nd person singular informal subject pronoun. It refers to the person being spoken to or written to. Unlike English "you", Spanish tú can only be used to address one individual and the individual must be someone with whom you are familiar. Do not use tú to address someone you do not know well or with someone who is in a position of superiority to you, e.g.: a doctor or elderly person (use the formal usted instead). Be sure to always write an accent on this subject pronoun to distinguish it from tu, the possessive determiner. When conjugating tú the verb ends in -as for -ar verbs and -es for -ir and -er verbs, e.g.: Tú hablas inglés porque vives en Canadá pero no sabes hablar español.

usted: This is the 2nd person singular formal subject pronoun to be used with people to whom you wish to show respect or do not have familiarity with, e.g.: doctors, professors, bosses, teachers, elderly people, etc. E.g.: ¿Usted me puede recomendar un buen medicamento para la gripa? The verb endings used with usted are: -a for -ar verbs, -e for -er verbs, and also -e for for -ir verbs. These are the same as the 3rd person singular endings used for él and ella shown next, e.g: Usted trabaja y vive en la ciudad, pero quiere vivir en el campo.

él: This is the 3rd person masculine singular subject pronoun, meaning "he". Verb forms for él in the present tense trigger the following agreement on verbs: -a for -ar verbs and -e for -er and -ir verbs, e.g.: Él dice que estudia y vive en Venezuela. Be sure not to confuse this pronoun with the masculine singular definite article el ("the"), which does not have an accent.

ella: This is the 3rd person feminine singular subject pronoun. Verb forms for ella in the present tense are the same as for él: -a for -ar verbs, -e for -er verbs, and also -e for for -ir verbs, e.g.: Ella limpia la cocina, barre el piso, y sale en la noche.

uno: Traditionally, this is considered a 3rd person singular indefinite subject pronoun that corresponds to "one" in English (e.g.: Uno debe seguir las reglas siempre. "One should always play be the rules.") This pronoun follows the same verb pattern as él, ella, and usted: -a for -ar verbs, -e for -er verbs, and also -e for -ir verbs, e.g.: Uno tiene que cuidarse. "One must take care of oneself."

nosotros/nosotras: This is the 1st person plural subject pronoun (i.e.: "we" in English). It must agree in gender with the group referred to. If the group has both males and females use the masculine nosotros form. Verbs agreeing with the subject nosotros/nosotras always end in -mos, along with the appropriate vowel depending on the verb ending, in present tense: -amos for -ar verbs, -emos for -er verbs and -imos for -ir verbs, e.g.: Nosotros preguntamos al profesor, leemos libros y escribimos ensayos.

vosotros/vosotras: This is the informal 2nd person plural subject pronoun, which might be translated as "you guys" or "you all". It must agree in gender with the group referred to. If the group has both males and females use the masculine vosotros form. Vosotros/vosotras is only used in Spain, with the rest of the Spanish-speaking world using ustedes in both informal and formal situations. Verbs that follow vosotros/vosotras end in -áis for -ar verbs, -éis for -er verbs and -ís for -ir verbs in the present tense, e.g.: Vosotros gastáis mucho dinero, perdéis mi tarjeta de crédito y decís que no hacéis nada mal.

ustedes: This is the formal 2nd person plural subject pronoun. It is used in formal situations in Spain and in both formal and informal situations in the rest of the Spanish-speaking world. Verbs agreeing with ustedes end in -an for -ar verbs and -en for both -er and -ir verbs in the present tense, the same endings used with ellos and ellas shown next, e.g.: Ustedes preparan la cena, recogen la sala y asisten a su clase de noche.

ellos/ellas: This is the 3rd person plural subject pronoun. It must agree in gender with the group referred to. If the group has both males and females use the masculine ellos form. Verbs that follow ellos or ellas end in -an for -ar verbs and -en for both -er and -ir verbs in the present tense, e.g.: Ellos están de vacaciones. Se divierten en el club por la noche cuando beben con amigos.

• It is important to know the subject pronouns in Spanish. However, it is equally important to know that they are not used as often as in English. English requires some kind of subject pronoun to be explicit in the sentence. Spanish, on the other hand, does not use subject pronouns most of the time, especially after a subject has already been introduced, because the information about who is doing the action of the verb is also contained in the verb ending that agrees with the subject, e.g.: Tomo agua en el parque. "I go to the park." The pronouns are included to introduce, emphasize, contrast or clarify the subject, e.g.: Nosotros vamos a la playa pero él va al cine. "We are going to the beach but he is going to the movies."
• Remember that vosotros/vosotras are only used in Spain.
• You should pay attention to the particular verb endings that accompany each subject pronoun in the different verb tenses/moods.
• Do not use subject pronouns yo or tú after prepositions, instead you must use prepositional pronouns mí and ti respectively. The other subject pronouns do occur after prepositions.