Children often produce nonadult responses to sentences with the focus operator only, such as Only the cat is holding a flag. For example, children often accept this sentence as a description of a situation in which a cat holds a flag and a duck holds both a flag and a balloon. One proposed analysis, by Paterson, Liversedge, Rowland & Filik (2003), contends that children disregard only in such sentences, yielding The cat is holding a flag. An alternative proposal by Crain, Ni & Conway (1994) maintains that children misassign only to the VP, yielding The cat is only holding a flag. The findings of experimental studies with two typologically distinct languages, English and Mandarin Chinese, support Crain et al.’s (1994) analysis. We propose, further, that children pass through a stage at which only is analyzed as a sentential adverb taking scope over both the subject NP and the VP. We address the questions of why children initially adopt this analysis, and how they converge on the adult grammars of these languages.