An approach providing the efficient use of speech synthesis in rendering text content as audio in a communications network. The communications network can include a telephony network and a data network in support of, for example, Voice over Internet Protocol (VoIP) services. A speech synthesis system receives a text string from either a telephony network, or a data network. The speech synthesis system determines whether a rendered audio file of the text string is stored in a database and to render the text string to output the rendered audio file, if the rendered audio is determined not to exist. The rendered audio file is stored in the database for re-use according to a hash value generated by the speech synthesis system based on the text string.