Guidelines for forming the Spanish imperative are:

• To use the imperative for Ud, add an a to the stem of verbs ending with (-er, and -ir), and an e to the stem of verbs ending with (-ar).

Examples: ¡hable usted! (talk!), ¡viva usted! (live!) ¡coma usted¡ (eat!), but remember there are some irregularities, you will see them in the table below.

• The second person singular (tú) forms are identical to the third person singular of the present tense.

Examples: El profesor habla. (The professor is talking.) ¡Habla tú! (Talk!)

• The first person plural (nosotros) is formed -in regular verbs- by changing the letter before -mos to either e or a depending on if the original verb is ending with (-ar, -er, or -ir). On irregular verbs different rules apply.

Examples: -ar: e ¡hablemos¡ ! estudiemos. -er: a like in (¡comamos!) -ir: a like in (¡abramos!)

• The second person plural (vosotros) forms are based on the infinitive, with a -d substituted for the final -r.

Examples: ¡Dormid vosotros! (Go to sleep, all of you!)

• The third person plural (ustedes) for -ar: e ¡hablen ustedes! For –er, -ir: a ¡vivan ustedes! ¡coman ustedes!

In general these are the variations, which occur to the ending of verbs including the Negative familiar commands, both singular and plural, are expressed by the present subjunctive:

• Regular -ar ending verbs: Take the present tense of the verb and change the (a) at the beginning of the suffix to (e).(for all the 5 grammatical persons)
• Regular -er ending verbs: Change the (e) at the beginning of the suffix after the stem to (a).( for all the 5 grammatical persons)
• Regular -ir ending verbs: For tú, Ud., and Uds., change the (e) at the beginning of the suffix after the stem to (a).

Nosotros: Change the (i) at the beginning of the suffix to (a). Vosotros: Change (í) to (ái).

-The present subjunctive is used for formal commands, both positive and negative: Duerma Ud. (Please go to sleep). It is also used for indirect commands (introduced by the conjunction que): Está cansado; que se acueste. (He's tired; let him go to bed.)

-For impersonal commands given in a general sense (directions on a bottle or an examination paper, for instance) the impersonal pronoun se is attached to the subjunctive:

• Agítese antes de usar.
  (Shake before using.)
• Escríbase en español.
  (Write in Spanish.)

Hortatory commands can be expressed either with the subjunctive or with the phrase vamos a and an infinitive:

• Durmamos.
  (Let's go to sleep.)
• Vamos a dormir.
  (Let's go to sleep.)

Object pronouns are attached to affirmative commands, but they precede negative and indirect commands:

• Tráigamelo Ud.
  (Bring it to me.)
• No me lo traiga Ud.
  (Don't bring it to me.)
• Que lo traiga Juan.
  (Let Juan bring it.)