Book excerpt: This is the very first book to investigate the field of phraseology from a learner corpus perspective, bringing together studies at the cutting edge of corpus-based research into phraseology and language learners. The chapters include learner-corpus-based studies of phraseological units in varieties of learner language differentiated in terms of task and/or learner variables, compared with each other or with one or more reference corpora; mixed-methods studies that combine learner corpus data with more experimental data types (e.g. eyetracking); and instruction-oriented studies that show how learner-corpus-based insights can be used to inform second language (L2) teaching and testing. The detailed analysis of a wide range of multiword units (collocations, lexical bundles, lexico-grammatical patterns) and extensive learner corpus data provide the reader with a comprehensive theoretical, methodological and applied perspective onto L2 use in a wide range of situations. The knowledge gained from these learner corpus studies has major implications for L2 theory and practice and will help to inform pedagogical assessment and practice.