Who is kissing whom? Two-year-olds’ comprehension of pronouns, case and word order

Two-year olds’ comprehension of pronouns in transitive sentences was examined. Previously, children at this age have been shown to comprehend transitive sentences containing full nouns and pronouns in subject position (Gertner et. al. 2006; Hirsh-Pasek & Golinkoff 1996;), but little is known about when children begin to comprehend the nominative and accusative case in pronouns. Using a preferential looking task, we found that 27-month-old children were able to comprehend transitive, grammatical sentences that had subject-verb-object (SVO) word order and nominative pronouns in subject position or accusative pronouns in object position, but 19-month-old children did not demonstrate this comprehension. Furthermore, neither group showed a consistent interpretation for ungrammatical sentences containing pronouns, in contrast to adult participants. Our results suggest that the ability to use pronouns as an aid to understanding transitive sentences develops by 27 months, before children are capable of producing these pronouns in their own speech.