Parallel phoneme labeling (PPL) for speaker-independent spoken word recognition

A main difficulty in speech recognition for unspecified speakers is due to the variation of the acoustic features between different speakers. In order to deal with this difficulty we introduce a parallel phoneme labeling (PPL) method. In this approach, all speakers in the world are assumed to be classified into a limited number of groups, within each group speakers have similar or close voice characteristics. Then, the phoneme labeling for each group is carried out in parallel. An unspecified speaker is assumed to be suitable to one of the parallel branches. Through experiments, the PPL method showed a better performance than the usual method with only a single universal reference pattern set.