In this study, the participants learned English as a foreign language (EFL) in the classroom and then worked on five learning tasks to apply their newly learned knowledge to unfamiliar environments. The participants took photos of people, objects, situations or scenarios and described them in detail using a mobile learning system. Familiarization strategies were developed for the participants to increase their knowledge of strange environments. We aimed to test the effectiveness of the familiarization strategies on learning performance in the mobile-assisted language-learning context. To this end, an experiment was carried out with fifty participants who were assigned either to the experimental or control groups. The participants in the former used the familiarization strategies, whereas the participants in the latter did not. We compared the learning performance of the participants in the two groups based on the scores of pre- and posttests with phrase translation, sentence translation and writing items. We also compared the EFL writing quality of the two groups on five tasks with respect to the amount, vocabulary, grammar, content, origination and creativity dimensions. The results of the pre/posttest comparison showed that the experimental group outperformed the control group on the writing item only. The results showed that the writing quality of the experimental group on the five tasks was significantly better than that of the control group in all of the six dimensions. In addition, all of the participants had positive perceptions of the usefulness of our learning system to assist their EFL learning in unfamiliar environments. The results suggest that familiarization strategies can significantly improve EFL learning performance in unfamiliar environments.