The 1st and 2nd person clitic pronouns me, te, nos, os can function either as the direct object or the indirect object of a verb, as can se when used as a reflexive or reciprocal pronoun. On the other hand, lo(s), la(s) and le(s) are constrained in terms of the direct ~ indirect object distinction, although in different ways in different parts of the Spanish-speaking world.

Except in Castile, Ecuador and Paraguay the predominant pattern (and the one recommended by the Real Academia Española) is the one shown in Table 1 below, which reflects the fact that lo, los, la and las descend from accusative Latin forms while le and les descend from dative forms:

 

Table 1     The ‘standard’ use of 3rd person clitic pronouns

	Direct object		Indirect object
	Masc.	Fem.
Sing.	lo	la	le
Plu.	los	las	les

 

However, in the so-called leísta dialects of Castile, Ecuador and Paraguay there is, to varying degrees, a systematic tendency to use le(s) in contexts in which normative precept calls for lo(s) or la(s).

 

Two of the commonest manifestations of leísmo are as follows. Firstly le(s) can replace lo(s) in the latter’s deictic funtion, i.e. when the pronoun is being used to address a person deferentially. This is illustrated in (1) below, where le appears in place of lo, the latter being the form predicted by Table 1.

 

(1)       No le mencionaron.

           ‘They didn’t mention you.’

 

Secondly le and, less commonly, les can be used to replace lo and los in their anaphoric function whenever the antecedent is [+ human] NP. Some examples of this anaphoric leísmo are as follows:

(2)       Su condición de candidato le coloca por encima del secretario general del partido.
            ‘His status as a candidate places him above the general secretary of the party.’

(3)       A Pedro le conozco desde hace muchos años.
            ‘I’ve known Pedro for many years.’

Again, the norm implied by Table 1 is one in which lo rather than le should occur in examples like (2) and (3).

Combining both of the foregoing manifestations of leísmo, a ‘basic’ leísta system can be set out as in Table 2 below.

 

Table 2    A basic leísta system

	Direct object				Indirect object
	Masculine			Feminine
	Anaphoric		Deictic
	Human Antecedent	Non-human Antecedent
Singular	le ~ lo	lo	le	la las	le
Plural	los ~ les	los	les		les

 

More extreme types of leísmo may also be encountered, particularly in Northern Castile.

 

In Castile, leísmo is often accompanied by laísmo, a term which refers to the use of la or (less commonly) las in the role of indirect object, as in (4) and (5) below.

 

(4)         La apetece más otra cosa que le haga falta, quizá.
             ‘She would prefer something else that she needs, maybe.’
             (España Oral: ACON017A; Corpus del Español)

 

(5)         La ha quedado muy bien la cocina.
             ‘Her kitchen has turned out very well.’

 

Unlike leísmo, which is socially unstigmatized, laísmo is regarded as unacceptable by many speakers.