Background: This small-scale study investigated English vocabulary exposure from graded readers and teacher talk in Grade 3 classrooms in poorly resourced township schools in South Africa. Vocabulary is one of the key building blocks for becoming a fluent reader. Most words are learnt through incidental exposure to oral or written language. Objectives: This study is a first attempt to investigate opportunities for incidental vocabulary exposure in poorly resourced classrooms in South Africa. Method: A corpus linguistics approach was used to analyse a written corpus of 57 143 tokens and a spoken corpus of 12 242 tokens. Results: The study showed that there are vast differences between levels of written and spoken vocabulary in the classrooms and that the role for oral vocabulary exposure in classrooms is restricted. Spoken vocabulary registered above the K-3 word frequency level largely came from teachers' read alouds of print materials. Conclusion: The study findings show that even in contexts where print exposure is limited, oral language cannot compensate for the richness of written vocabulary. Situational constraints, such as lack of books, negatively influenced the effective use of graded readers. Opportunities for incidental vocabulary learning, as well as implications for policy and further research, are discussed.