Much second language acquisition research in recent decades has assumed that a learner's main purpose for learning a second language (L2) is to develop communicative competence. Consequently, many studies have focused on investigating ways in which teachers and/or the learning environment may support the development of such competence. In particular, it has been argued that L2 learning is facilitated when learners interact, particularly in conversation with native speakers. Further, natural settings in which the learner is in contact with native speakers appear to lead to a higher level of L2 proficiency. Studies of learners of Arabic tend to agree with this view. Native Arabic-speaking contexts are of course diglossic, with local and standard varieties being used for different purposes. Research suggests that students believe it is most useful to learn the local variety of Arabic--the colloquial variety--for the sake of communication with native speakers. This article reports on a study of beliefs about learning L2 Arabic held by students of 61 nationalities at the Institute for the Teaching of Arabic to Non-Arabs (ITANA), in Riyadh, Saudi Arabia. Analysis of data from questionnaires and interviews highlighted students' belief cluster, based on a perceived strong link between the Arabic language and Islam, the religion of the participants. Other elements of the cluster consisted of beliefs concerning the importance of grammar, memorization and accuracy, and also the relative value of learning local and standard varieties of Arabic. It was found that in the conservative educational culture of ITANA and the wider context of Riyadh and Saudi Arabia, students' own purposes for learning, which were largely religious, led to beliefs about Arabic learning that supported "traditional methods" of instruction and resisted attempts to introduce ways of learning based on communicative approaches. The findings remind us that learning context and learning purpose are powerful influences on beliefs about what is helpful for the process of L2 learning, and that where communicative competence is not the goal of such learning, beliefs may differ considerably from those reported in much of the contemporary literature.