Introduction

A strong ambition of many non-native English writers is to expand their vocabulary. One of the best ways to approach this is by reading as much as possible.Many learners also use dictionaries  and word lists to try to increase the number of words they know. But how effective are these resources, and how many words are actually retained and, importantly, employed by writers in their  essays and assignments?
The answer is likely to be very few. While reading and looking up words in a dictionary can improve receptive vocabulary (understanding words when hearing or reading them), it is less effective  for developing productive vocabulary (actively producing appropriate words when writing). Learners often feel frustrated when writing in English because they cannot find the words to  express their ideas effectively. The reason is primarily the limited words at their disposal and the worry that the words they do know are too ‘unacademic’ and therefore unsuitable. Increasing  one’s receptive vocabulary is certainly useful, but productive vocabulary is the key to writing well in English and producing good academic work. Expand Your English has been designed for this  purpose, by targeting 200 key academic phrases* that learners may well have heard of, or even know how to use, but probably do not use as often as they should in their writing. Some of the terms may seem fairly obvious or familiar, but often non-native speakers fail to employ them in their writing and either fall back on the ‘safe’ elementary term or use a phrase or metaphor  picked up socially. It is also important to remember 

* The 200 terms were chosen based on how frequently they occur in academic writing (drawn from three academic corpora), how useful they are to non-native speakers, and how likely they are  to be missing from a learner’s productive vocabulary. They were selected after consulting three academic written English corpora: the British Academic Written English Corpus (BAWE), the  academic word list of the Corpus of Contemporary American English (COCA), and the academic word list devised by Averil Coxhead at the University of Wellington. COCA listed the words by  the frequency with which they occurred in published academic texts, so this was used as a base upon which I added the other two word lists and looked for matches. Words featuring in West’s  General Service List (GSL) (1953) were rejected, as were any others deemed by me to be in frequent current use (after consulting my own personal collection of 600 essays written by Chinese  postgraduates—on the condition they had been used correctly—that I had proofread between 2006 and 2015). The terms appearing only on a subject-specific list were then further scrutinized for their suitability. The most frequent 200 words (top of the COCA frequency list plus featuring in BAWE and Coxhead minus appearing in West and rejected through my own  judgement) were then selected, and an attempt was made to include the remaining 1,000 or so in Part B of the book.

that there is just as much worth in knowing when not to use a certain word as when to use it.
There are three key areas to consider when trying to increase productive vocabulary, and these are the foundation of Expand Your English. They are essential to retaining the learnt words and  retrieving them when needed.

Understanding: knowing the various definitions of the term and the words the term is used alongside
Context: knowing when and how to use the term
Familiarity: encountering the term regularly and in various contexts
In order for writers to retain, retrieve, and reuse the 200 terms that form Part A of the book, they have been divided up into sets of ten. Each set is introduced and then revisited. The three areas  (understanding, context, and familiarity) that the book concentrates on will aid this process of remembering and retaining. In this part, the reader may choose to tackle each set of ten terms in  order and work his or her way through the book. Alternatively, an effective way to retain and embed the terms into memory is to read the first stage of each set, do the first checks, and then  move on to set two. Once all twenty sets have been read and the questions answered, the reader can advance to the second stage of set one and so on.
BEGIN
SET 1 First stage: read through
SET 1 First check: complete the exercises
SET 2 First stage: read through
SET 2 First check: complete the exercises
When all the first stages are complete, proceed to the second stages.
SET 1 Second stage: read through
SET 1 Second check: complete the exercises
The second part of the book categorizes key academic terms according to function, meaning, and the areas of an essay in which they are likely to be relevant. Again, context and familiarity are  the objectives. Some of the 200 key words reappear in this part, to reinforce the learning. An index is also provided, with chapter numbers rather than page numbers to encourage the reader to search for the term within the entries and form links rather than be directed to the exact location.
Dictionaries are usually consulted only when a new word is encountered.Expand Your English shows the learner which words to encounter for effective and professional academic writing. As  mentioned, the only way to increase productive 
vocabulary is to explore words in detail and to keep revisiting them—that is the reason part one is dedicated to only a handful of words. Revisiting the terms later (having learnt many others in  between) will help the reader to embed the terms and increase their familiarity. Soon they will be in productive vocabulary ready for the next assignment. 
It is a pity when good subject knowledge and creative ideas are undermined by weak or repetitive writing. The 200 key terms and countless others contained in Expand Your English will go a  long way to preventing this common problem from occurring in the papers of students and researchers at academic institutions.