The importance of word frequency for vocabulary development is generally agreed on (e.g., Ellis, 2002; Webb, 2014): the more frequently learners encounter a lexical item, the more likely they are to acquire it. As a result, it has been argued that it is beneficial for language learning if vocabulary input is structured in a way that ensures repeated encounters with target vocabulary. In the foreign language classroom, where the language input is limited, it can be difficult for the individual teacher to ensure that learners are encountering target words frequently enough (cf. Schmitt, 2019). Teaching materials can thus play a valuable role in the language classroom by being the source of structured vocabulary input, where target vocabulary is systematically recycled. Studies have evaluated teaching materials and their function as learning tools by investigating the amount of recycling in the books, using either the raw frequency of words or a type-token ratio. However, given that some words are inherently more frequent in the language, figures representing the extent of recycling may be misleading, as the recycled items may be words already known to the target students. 

This paper presents a corpus-based textbook analysis where recycling is investigated numerically and the nature of the recycled items is also considered, that is, how frequent the recycled items are in general discourse. The corpus encompasses the texts from five series of intermediate EFL materials used in Swedish secondary schools (years 7–9)­. Lemmas occurring ten or more times were considered frequently recycled and thus possible to learn from the exposure. As the target students are intermediate learners, particular attention was paid to the amount of recycled mid-frequency vocabulary (cf. Schmitt & Schmitt, 2014) in the materials.

The results indicate that although a considerable proportion of the lexical input is recycled ten or more times in the materials, the vast majority of the recycled items are high-frequency words, which students are likely to already know. Considering the target students, this means that the recycling figures cannot be considered favorable for vocabulary development. It thus appears that investigations of the recurrence of words may have to be complemented with analyses of their frequency profile to understand the vocabulary learning opportunities in language learning materials.