Part 1: Distinguishing between Active and Passive Vocabulary
It is estimated that most language users have an active vocabulary of roughly 15,000 to 20,000 words, although the 1,000 most frequently used words make up approximately 90% of most written work.

Active vocabulary refers to words that an individual can actively recall and use appropriately in language production (speech and writing).
Passive vocabulary refers to words that an individual can recognize and understand in language reception (listening and reading) only.

Part 2: Academic and Scientific Vocabulary
Academic vocabulary can be divided into two types:

Technical academic vocabulary is words that are unique to certain academic disciplines. These are specialized terms, and they are generally only learned and used by students and researchers within that discipline.
General academic vocabulary is words that are used across disciplines for a broad range of academic writing purposes. Vocabulary of analysis or vocabulary related to the research process are examples of general academic vocabulary.

Part 3: Academic Word Lists and Phrasebanks
The Academic Word List (AWL) was created from general academic vocabulary and contains 570 word families and over 2000 words in total (Coxhead, 2000). This word list is based on a corpus of over 3.5 million words drawn from academic books and journals in a wide range of disciplines.

The Academic Phrasebank, developed by the University of Manchester, can also be a useful resource for scientific writing. For example, by clicking the link to "explaining causality," we are presented with nouns, verbs, prepositions, and connectors used frequently to show causality.

Part 4: English Language Corpora
A language corpus (plural corpora) is a large collection of texts that have been collected and organized for the purposes of linguistic research. Corpora exist for both written and spoken speech and for general as well as academic English.

Several commonly used corpora are listed below along with features of each:

Title	Word Count	Time Period	Features and Sources
NOW (News on the Web) Corpus	2.8 billion	2010-present	Online newspapers and magazines Updates daily as new sources go online
COCA (Corpus of Contemporary American English)	520 million	1990-2015	Balanced academic and general Balanced written and spoken American English focus
BNC (British National Corpus)	100 million	1980-1993	Balanced written and spoken British English focus
TIME Magazine Corpus	100 million	1923-2006	From 275,000 articles written in TIME Magazine

Part 5: Using COCA (Corpus of Contemporary American English)
The Corpus of Contemporary American English (COCA) was developed by Brigham Young University and is frequently used by linguists and researchers from many academic disciplines.

Learning to search COCA is not hard. After you go to the site, you can simply type terms into the search box to find results. It is helpful to click on the "sections" button below the search box because then you are able to customize your search. For example, you can specify that the search will occur only for spoken words, fiction, academic writing, newspapers, or a variety of other options.

You can also use the "insert POS" (POS stands for Part of Speech) button to ask COCA to search for only certain parts of speech for a word. Try an example yourself. Type a term such as "research" into the search box. Using the "insert POS" drop-down menu, you can add "verb.all." If you complete this search, COCA will return only examples where the word "research" is used as a verb. Many other options such as "verb.ED" and "verb.[DO]" exist as well, so you need to experiment to customize your search exactly the way you want.

Another interesting feature of COCA is that after completing a search, you are presented with an entire list showing the full range of words that appear next to your search term. Importantly, each entry is clickable as well, giving you a complete list of the exact sentences containing this combination of words. Information such as this can be invaluable for academic writers struggling to find appropriate words or phrasing in their writing.

Part 6: Using Google Search
Although not as customizable as COCA, Google search can help as well, particularly if you use quotation marks and asterisks in your searches.

Use quotes

" "

Find only the exact phrase you enter: "research indicates"

Use asterisk

*

Use an asterisk to find an unknown word: "a * amount of research"

In the above example using the asterisk, results will reveal common words that come before "amount of research." Browsing through search results reveals phrases such as "a significant amount of research" with 391,000 results and "a vast amount of research" with 317,000 results.

Again, information such as this can assist scientific and academic writers in many ways.

Coxhead, A. (2000). A new academic word list. TESOL Quarterly, 34(2), 213-238. doi:10.2307/3587951