1. In a speech analysis system for recognizing at least one predetermined keyword in an audio signal, each said keyword being characterized by a template having at least one target pattern and each target pattern representing at least one short-term power spectrum, an analysis method comprising the steps of forming a sequence of electrical signals repesenting a sequence of selected patterns, identifying electrical signals representing a candidate keyword when said sequence of selected patterns corresponds respectively to the sequence of target patterns of said keyword template, normalizing electrical signals representing the time duration spacings between selected patterns corresponding to said candidate word, and applying a prosodic test to said normalized time duration spacings, wherein said normalized time duration spacings for a candidate word must meet the timing criteria imposed by said prosodic test before said candidate word is accepted as a recognized keyboard.