This book focuses on vocabulary acquisition in the areas of English language learning either in a foreign or a second language environment. Starting from the social phenomenon that a large number of Mainland Chinese students obtain their further education in Western universities, the author carries out a longitudinal study by using instruments of vocabulary levels tests, questionnaires and interviews. On the basis of an in-depth investigation of vocabulary strategy usage by Chinese learners in widely differing environments, the author develops a model of vocabulary acquisition. This is the first model to combine both linguistic and non-linguistic strategies, motivation, and the stages of vocabulary learning into one comprehensive representation of vocabulary acquisition. The book not only offers a solid data base but also suggests effective strategies to enhance English language teaching and learning.