Corpus of Contemporary American English was released on the web in 2008 with more than 400 million words of corpus, the largest free web-based corpus. However, what makes this corpus special is not its enormous size but its :
1- genre-balanced search ability , as you can look up the word or collocation in any genre available ( or in all) and compare between spoken, fiction, popular magazines, newspapers, and academic, or even between sub-genres (or domains), such as movie scripts, sports magazines, newspaper editorial, or scientific journals
COCA_genre
2- over time search, as you can compare different years from 1990 to the present time
COCA_genreandtime
3- “.. semantically-based queries of the corpus. For example, you can contrast and compare the collocates of two related words (little/small, democrats/republicans, men/women), to determine the difference in meaning or use between these words [ also how each is used in different genres]”
COCA_comparingwords

4- interface, as you can easily conduct searches between all genres and years. You can have your search result listed as frequency  or relevance or as a chart. All of this is made possible because of the window frames.
Frame 1 : Navigation
COCA_navigation

Frame2:  Query Result (including frequency and word collocation)

COCA_queryresult


Frame3: The query in context (Key Word in Context) and the source text extract.
COCA_KWIC
5- Great tutorial that takes about 5 mins to complete. Help is always there if you need it.

The following video is a tutorial to show you how to use COCA and its great features.( Please use your headphones as the audio volume is low)




How to use it in the language classroom


1- You could do a vocabulary activity sheet same as the one embedded below. In such worksheet you turn the students’ attention to how words are used in authentic language and how each word behaves in a given sentence ( collocation with words but not with/more than others). You can also have students notice the nuance of difference between seemingly synonymous words and how each collocates with different words.
The worksheet below was constructed using COCA as a pre-reading vocabulary activity where students were introduced to  new lexis in context and asked to use context clues to figure out the meaning and asked about the collocation of each as well as semantic and syntactic significance of each.
vocabulary activity sheetgrade 8 mokey;s paw

2- You could do word part analysis worksheet where students practice on prefix or root words of new vocabulary to result in noticing of how words are formed. The document below was also constructed using the COCA and the wildcard (*) as a query ( I searched for the the prefix*, e.g. circum* to result in all words that start with circum-). After students formed the words ( working in pairs) they filled in the blanks  with the appropriate words in sentences cited from corpus. As such, students experimented with new vocabulary not in isolation but in authentic language.



3- You could have students derive a certain grammatical rule for the word “any” for example and when it is used. The options for using it in the classroom are endless.

Preparing corpus and concordancing for classroom use takes time and effort, and training for teachers/students too. The result is definitely one of satisfaction and enhancement of language learning as it is now learned using authentic language. Not only it changes the role of the students to a language explorer but also it aids in understanding English language ( from teachers’ and students’ perspective) like never before.
I hope this post was helpful enough :)
Any comments, suggestions, or queries are welcome in the comment feature.