Caller: Computer Assisted Language Learning from Erlangen - Pronunciation Training and More

In school, oral examination and the ability to speak a foreign language properly have become more important. Yet, individual time per pupil to train the correct pronunciation is extremely short. Caller is a program to support learning English including pronunciation training in class and at home. Its client/server architecture allows to run complex analysis programs like speech recognition on the server without having to consider computational restrictions of PCs. At the same time, the teacher has privileged access to monitor the students' progress. In this paper, technologies to evaluate the students' pronunciation are discussed: acoustic modelling, prosodic features, and pronunciation features.