During the development of a project, words used in source code add up to a big vocabulary, which may lead to a divergent word-understanding and wordknowledge between developers. Even the drop out of a single developer may lead to a big loss of knowledge about words and their meaning. By keeping track of the active developers vocabulary one is able to identify and react upon such situations. In this work we propose a way to identify these by analysing the words contained in identifiers obtained through the commit history in a version control system. A person’s vocabulary contains all words that they have used or have knowledge about, and can be subdivided in an active and passive part. The active side are all the words that the person uses in speech or in written form. In contrast, the passive vocabulary contains all words that one knows. The content of the vocabulary constantly changes. On the one side, it increases due to knowledge gaining, e.g. by reading books, and on the other side it decreases due to forgetting words. Using the commit history of a project one is able to compute the active vocabulary of each developer in the team and to verify if a shared team language can be identified. This work represents an excerpt of the study presented by the authors in [6].