The diachronic development of Differential Object Marking in Spanish ditransitive constructions

Differential Object Marking (DOM) in Spanish synchronically depends on the referential
features of the direct object, such as animacy and referentiality, and on the semantics of
the verb. Recent corpus studies suggest that the diachronic development proceeds along
the same features, which are ranked in scales, namely the Animacy Scale, the Referentiality
Scale and the Affectedness Scale. The present paper investigates this development in ditran-
sitive constructions from the 17th to the 20th century. Ditransitive constructions in Spanish
are of particular interest since the literature assumes that the differential object marker a is
often blocked by the co-occurrence of the case marker a for the indirect object. The paper
focuses on the conditions that enhance or weaken this blocking effect. It investigates three
types of constructions with a ditransitive verb: (i) constructions with indirect objects real-
ized as a-marked full noun phrases, (ii) constructions with indirect objects as clitic pronouns,
and (iii) constructions with non-overt indirect objects. The results clearly show that DOM is
more frequent with (iii) and less frequent with (i). Thus the results support the observation
that the co-occurrence of an a-marked indirect object (partly) blocks a-marking of the di-
rect object to a certain extent. Furthermore, the results show for the first time that indirect
objects realized as clitic pronouns without the marker a have a weaker blocking effect, but
still a stronger one than constructions without overt indirect objects. In summary, the paper
presents new and original evidence of the competition between arguments in a diachronic
perspective.