Research principles for word list development
The role and value of word list research for ESP
Developing and applying consistent principles for selecting lexical items for word lists is important because principles guide researchers in making many decisions in word list development. One principle could be that the items have to meet a particular frequency requirement in the corpus overall and in specific subject areas within a sub-corpus. For example, if a researcher wanted to develop a word list of Biomedical Science for first-year students, then a corpus might contain several sub-corpora of subjects such as Cell Biology, Chemistry, Human Biology, Psychology and Statistics, depending on the requirements of the degree. The frequency of lexical items in the whole Biomedical Science corpus overall would give an indication of candidates for a word list. The frequency of those candidates as they occur in each subject measure helps narrow down the possible candidates for the word list. This second measure of frequency in different sub-corpora relates to the range of occurrence of the words in a corpus.
Range concerns the occurrence of lexical items across several corpora, sub-corpora or texts. In the case of a corpus with sub-corpora, such as the example of the Biomedical Science corpus earlier, items which are shared across Cell Biology, Chemistry, Human Biology, Psychology and Statistics might be selected for a word list of Biomedical Science. On the other hand, items which occur only in one subject area, such as Cell Biology, might be selected for a word list for that particular subject only. In this case, the range principle could be applied across the texts in the Psychology sub-corpus. Hyland and Tse (2007) found differences in AWL word patterns and frequencies across subject areas in a corpus of university-level professional and student writers and argue that such differences add to the arguments against the common core approach.
The AVL (Gardner & Davies, 2014) was based on four key principles for selecting lexical items from their large sub-corpus of academic English through a corpus-comparison approach. The selection principles were frequency, range, dispersion and discipline. The frequency principle stated that frequency of the candidates for the word list had to be 50% more in academic texts than non-academic texts. The range principle involved two steps. The first was that items had to occur in at least seven of the nine disciplines in the academic corpus and the second was that they needed to occur with at least 20% of their expected frequency. While range ensures occurrences of lexical items across academic disciplines, the third principle of dispersion focuses on how evenly these items occur across the academic corpus. The final principle is to ensure that the range of disciplines needs to be taken into account to ensure that general academic vocabulary is selected, instead of technical vocabulary related to a discipline. It is important to understand the methodology and principled decisions of researchers in the development of word lists such as the AVL (for more on the word lists for general and specific academic purposes, go to Chapter 6).