The document discusses the potential advantages and challenges of using 3D virtual worlds for language learning. It outlines key features of 3D virtual worlds like realistic immersion through avatars and multimedia input. Potential benefits include opportunities for negotiation of meaning through interaction, engagement through artifact creation, and a sense of presence. However, challenges include the time needed for teacher and learner training on the technology, technical requirements, and long-term financial costs of creating and maintaining virtual worlds. Significant research found benefits when interfaces reduced constraints but also negative impacts from a lack of learner training and difficulties with communication tools.