1. A method for screening for diseases, the method comprising: performing a signal analysis of a speech sample received from a subject, the signal analysis comprising extracting human factor cepstral coefficients from the speech sample and identifying articulation range and articulation rate using the human factor cepstral coefficients extracted from the speech sample; determining a likelihood and type of a disease based upon the articulation range and articulation rate identified by the signal analysis of the speech sample; and outputting information indicating the likelihood and type of the disease.