Procedures are described for reducing the speech wave to a specification in terms of the time‐varying vocal‐tract resonances and source characteristics. The basic method, which has been called analysis by synthesis, involves the comparison of speech spectra with a series of spectra that are synthesized within the analyzer. Each comparison spectrum is generated according to a set of rules based on an acoustical theory of speech production. The result of the analysis of each input spectrum is a set of parameters that describes the synthesized spectrum providing the best match. In one version of the method convergence, towards the best match is controlled by the experimenter; in another version convergence to a match is accomplished automatically without the intervention of the experimenter. All the operations have been programmed on a general‐purpose digital computer and have been applied to the analysis of vowels and some consonants. The advantages of the analysis techniques are discussed.