Abstract
This paper investigates a general framework for synchronous educational language games that simultaneously allows researchers to crowdsource learner answers in a controlled environment. Our prototype Substituto allows teachers and students to interact in real-time while undergoing language learning exercises; ensuring that the learner's progress is not hurt by the introduction of crowdsourc-ing elements. We evaluate Substituto with a small-scale user study that focuses on training the use of English verb-particle constructions (VPCs), such as break down or take over, and test their use with second language learners of English of different proficiency levels over five pilot sessions. With the study we aim to ensure that our prototypical implementation behaves as expected and to identify any major design flaws that should be addressed. The preliminary results we achieved in order to evaluate the educational value, the user experience and the crowdsourcing capacity of Substituto confirm that it has the potential to become a valuable asset for language learning, a pleasant learning instrument and a crowdsourcing tool for collecting linguistic knowledge.