The general content of the three editions of the Duden dictionary has undergone few changes. The most substantial changes are the addition of syllabification and the deletion of antonomy in respect of lemmata in the second and third editions. The concept of dictionary subject matter is questioned, and it is argued that it is more appropriate to consider how the relationships between the classes of items interact with the function of the dictionary.
Untersuchungen Zur Kommerziellen Lexikographie Der Deutschen Gegenwartssprache I. "duden. Das Große Wörterbuch Der Deutschen Sprache in Zehn Bänden", 2003