Using le/les instead of lo, la, los, las


Sometimes in Spanish you will hear people use the Spanish le/les instead of the correct direct object pronouns lo/la/los/las for him/her/them. This is called leísmo. For example:

Abracé a mi padre.
I hugged my dad.
Le abracé. I hugged him. → leísmo
Lo abracé  I hugged him. → correct use

Abracé a mi madre. 
I hugged my mother.
Le abracé. I hugged her. → leísmo
La abracé.  I hugged her. → correct use

Ayudé a los estudiantes.
I helped the students.
Les ayudé. I helped them.  leísmo
Los ayudé. I helped them. →  correct use

Ayudé a las estudiantes.
I helped the [female] students.
Les ayudé.  I helped them.  → leísmo
Las ayudé. I helped them. → correct use

Transitive verbs that use a direct object pronoun need a direct pronoun lo/la/los/las, not an indirect object pronoun le/les. 

Leísmo is fairly common in Spain, in some areas more than others. It is often heard and also seen in written Spanish.

This incorrect use of the Spanish le/les is not accepted by the Spanish Royal Academy (R.A.E.) when it refers to her (singular) or them (plural), but it is accepted in the singular form le when referring to him.

Les invité. (I invited them.) → sometimes used but not accepted as correct.

Le invité. (I invited him.) →  sometimes used and accepted as correct by the R.A.E.

Les vi salir del bar. (I saw them leave the bar.) → sometimes used but not accepted as correct.

Le vi salir del bar. (I saw him leave the bar.) →  sometimes used and accepted as correct by the R.A.E.

There is also what is called leísmo de cortesía which is also accepted, when we are using a formal register, for example:

¿Le ayudo señor? (May I help you, sir?)

With verbos de afección psíquica, both types of pronouns (le/les and lo/los) are accepted. Some of these verbs are molestar, fastidiar, entretener, amenazar, aterrorizar ...

Esas películas le aterrorizan. (Those movies terrify him.)

Esas películas lo aterrorizan. (Those movies terrify him.)

No le molestes, que está haciendo los deberes. (Don't bother him, he is doing his homework.)

No lo molestes, que está haciendo los deberes. (Don't bother him, he is doing his homework.)

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