‘SE’ is one of those tricky words in Spanish that can drive “gringos” nuts. Here are the three main uses of ‘se’.
1. “SE” impersonal.
It works as a marker for impersonal constructions. In impersonal sentences, SE only serves to indicate the impersonal nature of the statement.
En los Estados Unidos se habla español.
Spanish is spoken in the United States.
2. “SE” pronombre reflexivo
In this case, SE is a reflexive pronoun for the third person (singular & plural).
Ellos se despiertan a las seis cada mañana.
They wake up at six o’clock every morning.
3. “SE” sustituto de le/les.
The personal pronoun SE is used as a variant of LE, LES (indirect object) in the third person when followed by LO, LA, LOS, LAS as a direct object.
El professor SE lo dio al estudiante.
The teacher gave it to the student.