Development of the NGSL was made possible through approved access to the Cambridge English Corpus (CEC). The CEC is a multi-billion word computer database of contemporary spoken and written English. It includes British English, American English and other varieties of English. It also includes the Cambridge Learner Corpus, developed in collaboration with the University of Cambridge ESOL Examinations. Cambridge University Press has built up the CEC to provide evidence about language use that helps to produce better language teaching materials.