The acquisition of control crosslinguistically: structural and lexical factors in learning to licence PRO

Rules for interpreting empty category (EC) subjects of complement clauses v ary crosslinguistically across structural and lexical dimensions. In adult Greek, a distinction is made between the verbs meaning WANT and TRY, the fo rmer but not the latter permitting the EC subject of its subjunctive comple ment to refer outside the sentence. The EC is pro for WANT and PRO for TRY. In adult Spanish, both the verbs meaning WANT and TRY require the EC subje ct (pro) to refer outside when the complement is in the subjunctive, and re quire the EC subject (PRO) to refer to the main clause subject when the com plement is in the infinitive. Twenty-three Greek-speaking four- to five-yea r-olds and 10 adults, 29 Spanish-speaking four- to five-year-olds, 18 six- to seven-year-olds and eight adults took part in act-out experiments. The r esults indicate an awareness of language-particular distinctions governing the interpretation of EC complement subjects. However, child speakers of bo th languages experience difficulty in giving sentence external reference, l eading to error in the case of subjunctive sentences for Spanish-speaking c hildren. We argue that the data overall is most compatible with children ha ving access to the empty category PRO by age four, and that failure to give external reference of an EC when required can plausibly be treated as perf ormance error. A picture verification task produced less clear results, but points to the need for data from younger children to establish whether the re is an early stage in which lexical semantics dominates children's interp retation of ECs.