Abstract: To improve the accuracy of phoneme discrimination, a first phoneme discrimination method composes analyzing, not only static information on a voice but also dynamic information on the voice, power variations of the voice as a power-change pattern (PCP) and spectrum parameter variations of the voice as a time spectrum parameter pattern (TSP). After rough clustering based on the PCP, detailed classification is conducted using the TSP so that the voice is hierarchically discriminated to obtain phoneme symbols. This invention also provides a second phoneme discrimination method. To improve the accuracy of phoneme discrimination by a recognition system for unspecified, independent speakers, plural spectrum parameter codebooks classified in advance depending on voice qualities are provided.