A learner-adaptive self-learning environment has been developed in which both mobile phones and personal computers can be used as client terminals. The learner-adaptive function has been implemented using SCORM 2004 specifications. The specifications were extended to enable offline learning using mobile phones. Because the application-programming environment of mobile phones varies from carrier to carrier, a common content format was specified for the learning content and content-execution mechanisms were developed for each carrier’s environment to maximize content-platform interoperability. The latest learning results achieved by using mobile phones were synchronized with the latest ones on the server-side sequencing engine so that the learner-adaptive function was available from personal computers as well. The system can provide adaptive courses such that the results of a pre-test taken on mobile phones can modify the lecture content on personal computers, fitting them to each learner’s level of knowledge and understanding. The functionality and usability of the system was evaluated through two trial experiments, the first of which involved adult learners and the second with small children and their parents.