Examined how rules for interpreting empty category (EC) subjects of complement clauses vary crosslinguistically across structural and lexical dimensions. Twenty-three Greek-speaking 4- and 5-year-olds and 10 adults, 29 Spanish-speaking 4- and 5-year-olds, 18 6- and 7-year-olds, and 8 adults took part in act-out experiments. Results indicate an awareness of language-particular distinctions governing the interpretation of EC complement subjects. (Author/VWL)