This paper reports on an ongoing project to develop an "eLingua" Latin language-learning application that combines natural-language text-input with computer game-based approaches to discovery learning. The program aims to create a content-based immersive environment within which to test the hypothesis that second-language learning is more effective from a starting point grounded in the familiar. The program design is motivated by the conviction that learning may best occur in a structured environment combining opportunities for active investigation and discovery with tools for traditional drill and practice. Such an approach involves the development of constructivist learning resources that integrate smoothly with didactic instructional requirements, and that employ novel user-interfacing. The design implements a range of content-based problem-solving approaches to language acquisition, alongside machine-based remedial feedback on natural-language text-input and Latin text-to-speech solutions.