Photo by Hana Ticha via eltpics on Flickr A friend of mine has mastered English - which is attested by a CPE certificate - by looking up a word and carefully studying examples in a dictionary every day before going to bed. It was before the days of online dictionaries, so he was using a copy of the excellent Longman Dictionary for Advanced Learners . In the 1990s learners' dictionaries, such as Longman or Oxford Advanced Learner's Dictionary (OALD), started breaking away from the native speaker dictionary format (such as dictionary.com ) by introducing two innovations. First, they started providing definitions using a controlled vocabulary - in the case of Longman it was the Longman Defining Vocabulary (LDV), a carefully graded list of the 2000 most frequent words in English, similar to West's General Service List (GSL). Second, they shifted the emphasis from purely defining meanings to highlighting usage through carefully chosen examples. As dictionary publishers moved