1. A database for use in a system for synthesizing a speech by concatenating a subset of a plurality of predetermined voice segments, the database comprising: a first table for associating each of said plurality of predetermined voice segments with pitch waveform IDs (identifiers) of pitch waveforms which, when combined in the listed order of said pitch waveform IDs, constitute a waveform of said each of said predetermined voice segments; and a second table for associating each pitch waveform ID with pitch waveform data identified by said each pitch waveform ID, wherein said second table is obtained by dividing each of said plurality of predetermined voice segments into pitch waveforms; classifying all of the pitch waveforms into groups of very similar pitch waveforms; and selecting one of said very similar pitch waveforms in each of said groups for said second table and wherein said very similar pitch waveforms in each respective one of said groups in said first table each have a same respective pitch waveform ID.