1. A system for asynchronously detecting one or more keywords in continuous speech, said system comprising: processor means responsive to a continuous speech signal for continuously developing a plurality of spectral estimates therefrom; generator means responsive to the plurality of spectral estimates for periodically generating digitized spectral parameters therefrom; first memory means for prestoring predetermined ones of dyad and triad subelement signals associated with one or more preselected keywords; correlation means for asynchronously correlating each of the prestored dyad and triad subelement signals of one or more preselected keywords with continuous sequences of the digitized spectral parameters to asynchronously produce a plurality of continuous correlation data signals; and a decision means for each desired keyword, each of said decision means being responsive to associated ones of the correlation data signals for developing an occurrence decision output whenever an associated keyword has been detected.