This book constitutes the thoroughly refereed post-conferenceproceedings of the Second International Conference on Software LanguageEngineering, SLE 2009, held in Denver, CO, USA, in October 2009.The 15 revised full papers and 6 revised short paper presented togetherwith 2 tool demonstration papers were carefully reviewed and selectedfrom 75 initial submissions. The papers are organized in topicalsections on language and model evolution, variability and product lines,parsing, compilation, and demo, modularity in languages, andmetamodeling and demo.