Longman American-English dictionaries are created using the Longman Corpus Network—a huge database of 330 million words from a wide range of real-life sources such as books, newspapers and magazines. All the information in our dictionaries, including example sentences, is based on the words in this network, so you see only real American English, as it's really used. So what’s in the Corpus Network? 

The Longman Spoken American Corpus 

The Longman American Spoken Corpus is a new project comprising 5 million words of text. The gathering of recordings was undertaken for Longman by the University of California at Santa Barbara. It represents the everyday conversations of more than 1,000 Americans of various age groups, levels of education, and ethnicity, and includes speakers from over 30 states. The recorded speech is transcribed onto a computer database and analyzed by our lexicographers to determine frequency of use, precise meanings and typical phrases that students need to study. 

The Longman Written American Corpus 

The Longman Written American Corpus is a dynamic corpus of 100 million words comprising text from: 

• newspapers 
• journals
• magazines
• best-selling novels
• technical and scientific writing
• even coffee-table books

The Longman Learners' Corpus 

Students and teachers throughout the world send in essays and exam papers to help us create the Longman Learners' Corpus, a 10-million-word computerized database made up entirely of language written by students of English. Every nationality, every language level is represented in the corpus and this provides an unprecedented insight into learner English. 

What Does It Tell Us? 

Each student essay is coded by nationality and language level (among other things), and then entered onto the computer to form part of the corpus. This allows our researchers to focus in on a selected group of students (such as Haitian low-beginning students), and then get an understanding of the specific problem areas this group might have. Or, our dictionary teams can use the essays to focus in on a word or a phrase and view the errors made by all the students. 

How Do We Use the Information? 

The Longman Learners' Corpus offers invaluable information about the mistakes students make and what they already know, and much of this information helps us when we create new dictionaries or update other dictionaries. For example, many of the Usage Notes in our dictionaries are based on data from the Learners' Corpus.

To learn more about which Longman dictionary is right for your classroom, visit us online at www.pearsonlongmanusa.com/dictionaries