Knowledge management systems are becoming embedded in knowledge work. As part of those knowledge management systems, increasingly, firms are developing best practices knowledge bases that summarize a wide range of enterprise processes. Central to those particular knowledge bases are common languages used to facilitate access and navigation through the knowledge base. This paper summarizes some of the evidence as to the necessity of common languages in best practices databases. Further, some barriers standing in the way of development and use of these common languages are summarized. In addition, this paper develops a model finding it is "impossible" to rationally choose a common language that meets needs of all individuals and the firm, unless dictatorship is allowed.