9. A method of establishing a call authentication system, the method comprising: receiving, by a processor of an authentication server, audio data including speech of a plurality of telephone calls; for at least a subset of the plurality of telephone calls, determining, by the processor, demographic data for a telephone caller making the telephone call; for at least the subset of the plurality of telephone calls, analyzing, by the processor, the audio data to identify a plurality of words from the speech of the telephone caller; receiving, by the processor, a plurality of word clusters, each word cluster associated with a specific demographic; populating, by the processor, at least one word cluster with at least a subset of the plurality of words from the speech of each telephone caller associated with the specific demographic based on the demographic data for the telephone caller; storing, by the processor, the populated at least one word cluster in a memory of the authentication server; for each word cluster, determining, by the processor, a plurality of associated words from among at least the subset of the plurality of words and an occurrence frequency for each of the plurality of associated words; and storing, by the processor, the determined associated words and occurrence frequencies in the memory.
9. A method of establishing a call authentication system, the method comprising: receiving, by a processor of an authentication server, audio data including speech of a plurality of telephone calls; for at least a subset of the plurality of telephone calls, determining, by the processor, demographic data for a telephone caller making the telephone call; for at least the subset of the plurality of telephone calls, analyzing, by the processor, the audio data to identify a plurality of words from the speech of the telephone caller; receiving, by the processor, a plurality of word clusters, each word cluster associated with a specific demographic; populating, by the processor, at least one word cluster with at least a subset of the plurality of words from the speech of each telephone caller associated with the specific demographic based on the demographic data for the telephone caller; storing, by the processor, the populated at least one word cluster in a memory of the authentication server; for each word cluster, determining, by the processor, a plurality of associated words from among at least the subset of the plurality of words and an occurrence frequency for each of the plurality of associated words; and storing, by the processor, the determined associated words and occurrence frequencies in the memory. 12. A method of authenticating a telephone caller, the method comprising using, by the processor, the call authentication system established by the method of claim 9 to authenticate the telephone caller.