1. A computer implemented speech recognition system, comprising: a communication system having one or more groups of users, each group of user having a group to group calling statistic that is a measure of whether the user of each group calls users of other groups of the communication system; a speech recognition engine that is part of the communication system and generates a set of voice command interpretations based on a voice command of a user and a set of grammar, the voice command including a name of a person; and the speech recognition engine further comprises a group unit that adjusts the grammar used by the speech recognition engine based on group to group calling statistics that modify a weighting of the grammar to facilitate the recognition of a name of a person used in the voice command.