The best way to learn is by having a good teacher and the best language learning takes place when the learner is immersed in an environment where the language is natively spoken. 3D multi-user virtual worlds have been claimed to be useful for learning, and the field of exploiting them for education is becoming more and more active thanks to the availability of open source 3D multi-user virtual world development tools. The research question we wanted to respond to was whether we could deploy an engaging learning experience to foster communication skills within a 3D multi-user virtual world with minimum teacher's help. We base our instructional design on the combination of two constructivist learning strategies: situated learning and cooperative/collaborative learning. We extend the capabilities of the Open Wonderland development toolkit to provide natural text chatting with non-player characters, textual tagging of virtual objects, automatic reading of texts in learning sequences and the orchestration of learning activities to foster collaboration. Our preliminary evaluation of the experience deems it to be very promising. (Contains 3 figures.)