11. A method for synthesizing a speech of an input phoneme sequence, comprising: storing a plurality of speech unit waveforms in a first memory; correspondingly storing speech unit information and an address of each of the plurality of speech unit waveforms in a second memory; selecting a speech unit sequence corresponding to the input phoneme sequence by referring to the speech unit information stored in the second memory; acquiring a speech unit waveform corresponding to each speech unit of the speech unit sequence from the first memory by referring to the address stored in the second memory; and generating the speech by concatenating the speech unit waveform acquired; wherein the acquiring step comprises copying by an acquisition unit at least two speech unit waveforms from a continuous region of the first memory onto a buffer by one access, a data quantity of the speech unit waveforms being less than or equal to a size of the buffer, the speech unit waveforms corresponding to at least two speech units included in the speech unit sequence.
11. A method for synthesizing a speech of an input phoneme sequence, comprising: storing a plurality of speech unit waveforms in a first memory; correspondingly storing speech unit information and an address of each of the plurality of speech unit waveforms in a second memory; selecting a speech unit sequence corresponding to the input phoneme sequence by referring to the speech unit information stored in the second memory; acquiring a speech unit waveform corresponding to each speech unit of the speech unit sequence from the first memory by referring to the address stored in the second memory; and generating the speech by concatenating the speech unit waveform acquired; wherein the acquiring step comprises copying by an acquisition unit at least two speech unit waveforms from a continuous region of the first memory onto a buffer by one access, a data quantity of the speech unit waveforms being less than or equal to a size of the buffer, the speech unit waveforms corresponding to at least two speech units included in the speech unit sequence. 18. The method according to claim 11 , wherein the input phoneme sequence is training data, and wherein the second acquiring step comprises counting a frequency of a combination of two speech units continuously appeared in the speech unit sequence; selecting the combination of two speech units in higher order of the frequency; and adjacently storing two speech unit waveforms corresponding to the combination in the first memory.