The constructs of complexity, accuracy and fluency (CAF) have been used extensively to investigate learner performance on second language tasks. However, a serious concern is that the variables used to measure these constructs are sometimes used conventionally without any empirical justification. It is crucial for researchers to understand how…

Vocabulary is an essential component of language. It is central to reading ability, writing ability and listening ability, and the most important aspect of second-language (L2) knowledge for academic achievement. The aim of this paper is to investigate quantitatively some of the factors that make some L2 words more difficult to learn and retain…