This research study considers the problem of Japanese university students who are studying the sciences in their native language, but who also may be expected to do at least part of their reading through textbooks written in English. The article presents a Science Textbook Word List (STWL), derived from a 700,000-word academic corpus compiled from English-medium textbooks intended for science majors. The STWL contains 309 word families, which accounts for 13.4% of the tokens in the science textbook corpus under study. The high word frequency and the wide text coverage of academic vocabulary throughout the science textbooks confirm that academic vocabulary plays an important role in science textbooks. The study also found that the STWL provided better coverage of the studied corpus than the widely used Academic Word List (AWL) (Coxhead, 2000), and another science word list (Coxhead & Hirsh, 2007). These results demonstrate that corpus-specific word lists provide more coverage of the intended texts with fewer items. This is of benefit to the students as the amount of learning time can be significantly reduced, and the effort put in to learn such lists is well repaid by the opportunity for using the vocabulary.
Keywords: word list, lexical coverage, vocabulary, EFL
IntroductionMany students enrolled as science majors in Asia attend lectures held in their first language, yet are required to read textbooks that are written in English (in Taiwan, see Hsu, 2014; in Indonesia, see Nurweni & Read, 1999; in Iran, see Valipouri & Nassaji, 2013; and in Thailand, see Ward, 2009). As knowledge of academic vocabulary is seen as an indispensable component of both academic reading ability and success (Dreyer & Nel, 2003;Nagy & Townsend, 2012;Schmitt, Jiang, & Grabe, 2011), it is imperative for learners to comprehend what is read. Unfortunately, due to the large amount of vocabulary found in English-medium academic texts, expecting students to know or learn this vast quantity of words may prove to be an unrealistic assumption of the teachers.One way to assist science majors with reading comprehension is to narrow the domain of language, providing learners with the specific lexical knowledge necessary to function in such an academic context. Nation (2001, 2008) recommends that students with lower-levels of English should focus on the general high-frequency vocabulary, such as West"s (1953) General Service List (GSL), while higher-level students who already have a strong command of the basic core vocabulary, such as many science majors, should focus on the lower frequency technical or academic vocabulary.Technical or domain-specific words are vocabulary related to a particular discipline (Martin, 1976).Jay Veenstra et al.The Journal of Asia TEFL Vol. 15, No. 1, Spring 2018, 148-166 149These items occur frequently in a specialized text of a subject area, but do not occur (or very rarely occur) in other fields (Nation, 2001). For example, words such as torque, thermodynamics, concave, refraction, and electroscope are examples o...