The Latin word imperare means "to have power", "to order" or "to command". But the imperative form in Spanish isn't just about bossing others around. We use it:
  • to give advice
Aprende esta regla.
Learn this rule.
  • to casually invite someone
Ven a comer a mi casa mañana.
Come eat at my place tomorrow.
  • to give instructions
Dobla la segunda calle a la derecha.
Turn right onto the second street.
  • to ask someone to do something
¡Cierra la puerta, por favor!
Please, close the door!
And so the verbs change:
Indicative Imperative
Hablas despacio.¡Habla despacio, por favor!
UstedesHablan despacio.¡Hablen despacio, por favor!
Note that if you are asking someone to do something, this form is not very polite, especially if you don't use por favor. If you don't know the person you are talking to well, it is always safer to use questions:
¡Habla despacio! → ¿Puedes hablar despacio, por favor?
The three conjugation groups
hablar aprender escribir
These verbs are irregular:
hacer → haz; hagan
decir → dí; digan
ir → ve; vayan