Vibrato and vowel identification

The influence of vibrato on vowel identification i s studied in synthesized vowel sounds with fundamental frequencies between 300 and 1000 Hz. Phonetically trained subjects were asked to identify these stimuli presented with and without vibrato a s any of 12 Swedish long vowels. Small and occasional effects a r e observed on the mean formant frequencies and the scatter between the responses. However, the effects a r e greater and more frequent$haai would be expected by chance. In a majority of the cases, where the vibrato affected the responses, the vowel identification became somewhat harder when the stimulus was presented with vibrato.