Deletion of optional double clitic in South American Spanish

We are exploring to what extend Uniform Information Density explains the deletion clitics in certain dialects of Spanish. Spanish in general requires the doubling of indirect objects (Example 1.1.). with a syntactically independent (and phonologically dependent) word called clitic. South American Spanish allows the doubling of the direct objects with a clitic which may or may not agree in number and gender with the noun phrase they corefer (Example 1.2.).

Example

Maria le  escribe una carta  a  Pedro.
      IO                     IO
Maria him writes  a   letter to Pedro.

Example

Lo         veo      el edificio. 
{it-Masc}  {I see}  the building.

Lo   veo     la niña. 
him  {I see} the girl.

Optional Double Clitic may occur along side the doubling of direct object as well. In such cases, the clitic undergoes phonological word transformation. "le lo" transforms to "se lo".