This document discusses the use of concordancers in corpus linguistics. It defines a concordancer as software that allows users to search corpora to analyze language patterns. Concordancers are useful for exploring word relationships and finding authentic examples of word usage. The document provides examples of concordancer tools and discusses their relevance for fields like lexicography, stylistics, and English language teaching. It summarizes a study that found ESL students had positive attitudes towards using concordancers to improve their vocabulary and writing skills.