this volume investigates the linguistic development of children with regard to their knowledge of the verb and its grammar. the selection of papers gives empirical evidence from a wide variety of languages including hebrew, german, croatian, japanese, english, spanish, dutch, indonesian, estonian, russian and french. findings are interpreted with a focus on cross-linguistic similarities and differences, without subscribing to either a ug-based or usage-based approach. currently debated topics, such as the role of frequency, as well as traditional ones such as bootstrapping are integrated into the presentation of language-specific, learner-specific and more general properties of the acquisition process. the papers are united by their focus on discovering what determines rule-governed behavior in language learners who are coming to terms with the grammar of verbs.