Many elements contribute to the relative difficulty in acquiring specific aspects of English as a foreign language (Goldschneider & DeKeyser, 2001). Modal auxiliary verbs (e.g. could, might), are examples of a structure that is difficult for many learners. Not only are they particularly complex semantically, but especially in the Malaysian context reported on in this paper, there is no direct equivalent in the studentsâ L1. In other words, they are a good example of a structure for which successful acquisition depends very much on the quality of the input and instruction students receive. This paper reports on analysis of a 230,000 word corpus of Malaysian English textbooks, in which it was found that the relative frequency of the modals did not match that found in native speaker corpora such as the BNC. We compared the textbook corpus with a learner corpus of Malaysian form 4 learners and found no direct relationship between frequency of presentation of target forms in the textbooks and their use by students in their writing. We also found a very large percentage of errors in studentsâ writing. We suggest a number of possible reasons for these findings and discuss the implications for materials developers and teachers.