Abstract: A method and system for selecting formant trajectories based on input speech and corresponding text data. The input speech is analyzed to obtain formant candidates for the respective time frame. The text data corresponding to the input speech is converted into a sequence of phonemes which are then time aligned such that each phoneme is temporally labeled with a corresponding segment of the input speech. Nominal formant frequencies are assigned to a center timing point of each phoneme and target formant trajectories are generated for each time frame by interpolating the nominal formant frequencies between adjacent phonemes. For each time frame, at least one formant candidate that is closest to the corresponding target formant trajectories is selected according to a minimum cost factor. The selected formant candidates are output for storage or further processing in subsequent speech applications.

Abstract: A speech synthesis method employs an acoustic element database that is established from phonetic sequences occurring in an interval of a speech signal. In establishing the database, trajectories are determined for each of the phonetic sequences containing a phonetic segment that corresponds to a particular phoneme. A tolerance region is then identified based on a concentration of trajectories that correspond to different phoneme sequences. The acoustic elements for the database are formed from portions of the phonetic sequences by identifying cut points in the phonetic sequences which correspond to time points along the respective trajectories proximate the tolerance region. In this manner, it is possible to concatenate the acoustic elements having a common junction phonemes such that perceptible discontinuities at the junction phonemes are minimized. Computationally simple and fast methods for determining the tolerance region are also disclosed.