Inter-textual Vocabulary Growth Patterns For Marine Engineering English

This paper explores the three fundamental issues concerning the inter-textual vocabulary growth patterns for marine engineering English. They are distributions of vocabulary sizes of individual texts, vocabulary growth models, and newly occurring vocabulary distributions of cumulative texts. The research is carried out on the basis of the MEE corpus.The vocabulary sizes of individual texts with the same text size conform closely to the normal distribution. Four existing models (Brunet's model, Tuldava's model, Guiraud's model, and Herdan's model) are tested against the empirical growth curve for marine engineering English. A new growth model is derived from the logarithmic function and the power law. The theoretical mean vocabulary size and the 95% upper and lower bound values are calculated as functions of the sample size.This research has significance in explicit EFL teaching and learning. The new growth model can make accurate estimates not only on the vocabulary size and its intervals for a given textbook but also on the volume of texts that are needed to produce a particular vocabulary size.