This book offers an insightful description of the productive behavior of four-character schematic idiomatic expressions (SIEs) in Mandarin and explores from a usage-based perspective the issue of how young learners acquire the partial productivity of these expressions. The beginning chapters contribute to a constructional understanding of the quadri-syllabic SIEs and an in-depth distributional analysis of three typical schematic patterns based on natural corpus data. The following chapters present detailed reports on four experimental studies to account for the factors that play significant roles in the learning process of SIEs from adolescence to adulthood. In the final chapter, the author concludes that acquisition of SIEs is as an interactive process shaped by input frequency, structural complexity, internal semantic relation, and chunking effect of open morphemes at different age levels. These findings enrich current understandings on constructional idioms and the emergentist model in idiom learning with a cross-linguistic focus on Mandarin unique quadri-syllabic SIEs. Language teachers, researchers, and postgraduate students who are interested in studies of idiomaticity. Construction grammar and usage-based learning model will find this book sufficiently informative and intriguing.