Previous studies reported that children made errors by identifying constituents outside of the c-command domain of only as focus. (Crain et al. 1992, 1994; Notley et al. 2009; Gualmini et al. 2003). In order to provide a more detailed picture of the developmental knowledge about the syntactic constraint, this study investigates how children and adults assign focus in sentences with post-verbal only preceding the two noun phrases connected by prepositions either about or to (i.e., NP1 about NP2 and NP1 to NP2). Only is associated with both NP1 and NP2 in sentences involving 'about' whereas it is associated with NP2 alone in sentences involving 'to'. Using a Truth-Value Judgment task (Crain & Thornton 1998), I demonstrate that unlike adults, children have a strong tendency to treat two different constructions in the same way and prefer to associate only with the NP2 in general. The result indicates that children have a qualitatively different syntactic representation in terms of the c-command constraint.
2. Theoretical Background