WriteBetter is a learning tool for written English that leverages the Data-Driven Learning (DDL) approach. DDL refers to an approach to learning foreign languages in which students discover patterns or rules of language use autonomously by exploring a large amount of sentences written by native speakers. To do so, WriteBetter offers a function through which students can search words to discover how to use them by exploring real sentences that contain that words. WriteBetter also has a function with which students can explore the most frequent language structures related to the words searched. Students can also enrich their texts by looking up words in an integrated dictionary, which provides definitions, synonyms, and examples. This dictionary is WordNet, a large lexical database of English published by Princeton University. The corpora that WriteBetter uses are Wikipedia articles, and around 3,000 public domain English books.