This book investigates the acquisition of pronominal elements by monolingual children acquiring English and Brazilian Portuguese as their native languages. Previous studies have found non-adult behavior in childrens use and comprehension of pronouns in two syntactic contexts: resumptive pronouns in relative clauses and anaphoric pronouns bound by argumental noun phrases. Children perform similarly on both contexts, incorrectly accepting these cases at chance level. The age-range when this chance performance is detected is the same in both cases, around 4 and 5 years.