Relation between speech context and vowel perception

Several tests were carried out to identify synthetic vowel sounds, in isolated form and in natural word context. Clear shifting of phoneme limits was shown for three different phoneme transitions. The examples lead to the conclusion that the general procedure of vowel perception, and the allocation of the sound event to a certain German phoneme, is not determined by a rigid classification scheme. Similar shift of phoneme limits may be expected for consonants. A complicated dynamic adaptation will be necessary for an automatic speech recognition system, if speakers are to use all freedoms of natural speech.