This volume focuses on the acquisition of tense-aspect morphology in L1 Italian children learning L2 English and in L1 English children learning L2 Italian. This bidirectional design, where two languages represent both the source and the target, is geared towards showing the effects of language transfer in learners that, because of their age, have the potential of becoming native-speakers of the target language. What makes child SLA interesting is its having the characteristics of both L1 acquisition and adult L2 acquisition.