1. A computer-implemented method for facilitating communication, comprising: generating, for a plurality of words in a chat vocabulary, word metadata characterizing a grammatical function for the words in the chat vocabulary; assigning each of the plurality of words in the chat vocabulary to one or more semantic categories in an ontology; obtaining a plurality word combinability rules for combining one or more words assigned to a first one of the semantic categories with one or more words assigned to a second one of the semantic categories, based on the word metadata and the ontology; and dynamically generating phrases to include in chat messages according to the plurality of word combinability rules.