Temporal decomposition of speech

In articulatory phonetics speech is described as a sequence of distinct articulatory gestures, each of which produces an acoustic event that should approximate a phonetic target. Due to the overlap of the gestures these phonetic targets are often only partly realized. Atal (1983) has proposed a method for speech coding based on so-called temporal decomposition of speech into a sequence of overlapping target functions and corresponding target vectors. The target vectors may be associated with ideal articulatory positions. The target functions describe the temporal evolution of these targets. This method makes no use of specific articulatory or phonetic knowledge. We have extended and modified this method to improve the determination of the number and the location of the target functions and to overcome the shortcomings of the original method. With these improvements temporal decomposition has become a strong tool in analysing speech, from which researchers working on speech coding, recognition and synthesis may profit.