The Distribution Of Word Families In College English Textbooks

Vocabulary is of vital importance in College English teaching, but it is also an area that is perceived as being difficult to tackle. Accordingly, the concept of word family is introduced because it can reflect the inherent relationship between words, provide guidance in vocabulary teaching, strengthen learners'lexical grammar, and reduce their vocabulary learning burden. From the perspective of word family, based on a corpus composed of four sets of College English intensive reading textbooks, and by using three word family lists processed from Defining vocabulary, CET-4 and CET-6 vocabulary, the following issues are addressed in this research:1. The vocabulary size and hapax legomena in the four sets of College English intensive reading textbooks in terms of word types, lemmas and word families;2. The vocabulary growth patterns of the four sets of textbooks;3. The lexical density of the four sets of textbooks;4. The lexical coverage of the four sets of textbooks over CETW4, CETW6 and DW, and the lexical repetition of CETW4, CETW6 and DW in the four sets of textbooks.The results reveal that:1. The vocabulary size of the textbooks decreases greatly after lemmatization (about 2,000-3,300 words), and further reduces after turning lemmas into word families (about 1,200-1,800 words); the proportion of hapax word families taking up in the total number of word families in the textbooks is less than the proportion of hapax lemmas and much less than that of hapax word types.2. The inter-textual vocabulary growth patterns of the four sets of textbooks can be better described by the word family growth curves; the Brunet's model proves to be good for the description of the inter-textual vocabulary growth for the four sets of textbooks, therefore, by virtue of this model, it is found that none of the four sets of textbooks'vocabulary coverage over naturally occurring 2,000-words texts reaches 95% coverage rate.3. In terms of the lexical density, the arrangement of teaching materials in some sets of textbooks are not sequenced according to band difficulty and text difficulty.4. The Lexical coverage of the textbooks over DW is the highest, over CETW4 is relatively low, and over CETW6 is the lowest; compared with CETW4 and CETW6, proportion of the DW word families recycled 5 or more times in the four sets of textbooks is the highest.