We are pleased to present the proceedings of the Second International Conf- ence on Software LanguageEngineering (SLE 2009). The conference was held in Denver, Colorado (USA) during October 5-6, 2009 and was co-located with the th 12 IEEE/ACM International Conference on Model-Driven Engineering L- th guages and Systems (MODELS 2009) and the 8 ACM International Conf- ence on Generative Programming and Component Engineering (GPCE 2009). TheSLEconferenceseriesisdevotedtoawiderangeoftopicsrelatedtoarti?cial languages in software engineering. SLE is an international research forum that brings together researchers and practitioners from both industry and academia to expand the frontiers of software language engineering. SLE'sforemostmissionis to encourageand organizecommunicationbetween communities that have traditionally looked at software languagesfrom di?erent, more specialized, and yet complementary perspectives. SLE emphasizes the f- damental notion of languages, as opposed to any realization in speci?c technical spaces. In this context, the term "software language" comprises all sorts of - ti?cial languages used in software development, including general-purpose p- gramming languages, domain-speci?c languages, modeling and meta-modeling languages, data models, and ontologies. Software language engineering is the application of a systematic, disciplined, quanti?able approach to the devel- ment, use, andmaintenanceoftheselanguages. TheSLEconferenceisconcerned with all phases of the lifecycle of software languages; these include the design, implementation, documentation, testing, deployment, evolution, recovery, and retirement of languages. Of special interest are tools, techniques, methods, and formalisms that support these activities. In particular, tools are often based on, or automatically generated from, a formal description of the language.

Models have become essential for dealing with the numerous aspects involved in developing and maintaining complex IT systems. Models allow capturing of the relevant aspects of a system from a given perspective, and at a precise level of abstraction. In addition to models, the transformations between them are other key elements in model-driven engineering. Model transformations allow the de?nition and implementation of the operations on models, and also provide achainthatenablestheautomateddevelopmentofasystemfromitscorrespo- ing models. Furthermore, model transformations may be realized using models, and are, therefore, an integral part of any model-driven approach. There are already several proposals for model transformation speci?cation, implementation and execution, which are beginning to be used by modeling practitioners. However, model transformations need specialized support in s- eral aspects in order to realize their full potential. The problem goes beyond having speci?c languages to represent model transformations; we also need to understandtheirfoundations,suchasthekeyconceptsandoperatorssupporting those languages, their semantics, and their structuring mechanisms and pr- erties (e. g. , modularity, composability and parametrization). In addition, model transformations can be stored in repositories as reusable assets, where they can be managed, discovered and reused. There is also a need to chain and combine model transformations in order to produce new and more powerful transfor- tions, and to be able to implement new operations on models. Finally, model transformations need methodology support, i. e. , they need to be integrated into software development methodologies supported by appropriate tools and en- ronments. These issues and concerns de?ne the focus of these proceedings.

This book constitutes the refereed proceedings of the 16th International Conference on Model Driven Engineering Languages and Systems, MODELS 2013, held in Miami, FL, USA, in September/October 2013. The 47 full papers presented in this volume were carefully reviewed and selected from a total of 180 submissions. They are organized in topical sections named: tool support; dependability; comprehensibility; testing; evolution; verification; product lines; semantics; domain-specific modeling languages; models@RT; design and architecture; model transformation; model analysis; and system synthesis.