Clitic omission, null objects or both in the acquisition of European Portuguese?

Previous studies have established a correlation between early clitic omission and the existence of past participle agreement, explainable with a maturational constraint – the UCC. Since Portuguese doesn’t show past participle agreement, it is expected that Portuguese children will produce clitics early on. I order to find out whether this correlation holds for Portuguese, an experimental study was conducted reproducing Schaeffer’s (1997) and adapting it to particular properties of Portuguese – the availability of null objects and variability of clitic position. The results of this study suggest that Portuguese children do omit clitics, apparently contradicting previous studies. Since clitic omission lasts until later than in other languages, we hypothesize that the explanation may rely on complexity factors.