We designed activities for learning English as a foreign language in a mobile learning environment with familiar authentic support for this study. Students learned at school and then applied their newly gained knowledge to solve daily life problems by first using a tablet to take pictures of objects they wished to learn about, then describing them and sharing their homework with peers. For this study two experiments were carried out in which 59 junior high school students participated. A class of 28 students served as the control group in Experiment 1, and as the experimental group in Experiment 2; a second class of 31 students served as the experimental group in Experiment 1 and as the control group in Experiment 2. In the class serving as the control group, students studied and completed each learning activity using traditional textbooks while the experimental group studied using an electronic textbook and used a learning system installed on tablet PCs. This study investigates the effects of the mobile system on learning achievement and cognitive load. The research resulted in three main findings. First, the experimental students outperformed the control students on post-test items in both experiments. Second, learning activities using the tablet learning system caused less cognitive load for the students than when learning without technological support. Finally, this study found that creating text annotations is very important learning behavior and it predicts learning achievement. Based on these results, several implications along with conclusions and suggestions for future research are suggested at the end of this study.