A corpus-based vocabulary analysis of first-year undergraduate textbooks of an international program in economics

The purpose of this current study was to (1) investigate the text coverage that provided by the BNC/COCA Word Family Lists (Nation, 2017) and the Academic Word List (Coxhead, 2000) in the first-year Bachelor of Economics International Program (BEIP) textbooks, (2) investigate the vocabulary size required to read the BEIP textbooks, and (3) identify the AWL academic words that occur most frequently in the BEIP textbooks. A corpus of 1,343,493 words from the economics course textbooks was compiled into the ECON corpus and then analyzed using the AntWordProfiler software program (Anthony, 2020). It was found that the 4th 1,000 BNC/COCA word family lists reached 96.10% and the 9th 1000 BNC/COCA word family lists reached 98.11% in the ECON corpus. The results in this current study implied that a vocabulary size of around 3,500–4,000 word families is needed for reading the BEIP textbooks that requires 95% coverage for reasonable comprehension, while a vocabulary size of approximately 8,500–9,000 word families is needed for reading the BEIP textbooks that requires 98% coverage for optimal comprehension. Moreover, the AWL accounted for 9.62% of the text coverage, while the first and second 1,000-word levels of the GSL gave a cumulative coverage of 79.71%. Regarding the most frequently occurring words, AWL academic words must be selected using Coxhead’s (2000) criteria, with the word frequency of at least 38 times and 4 times in each subcorpus. In this current study, there were 187 frequently-occurring AWL academic words and 133 AWL academic family headwords. The results of the ECON corpus compilation suggest curriculum developers and materials designers include these words and emphasize their importance in an economics textbook for effective word selection. The findings also suggest implications for instructional practices, and recommendations for future research.