Effect of Vowel Duration and Noise on the Perception of Stop-Glide Continuum

Abstract

The present study aimed to investigate the effect of vowel length and noise on perception of stop-glide continuum. A nine point stop-glide continuum was created by varying the onset frequency of second formant. The continuum was then manipulated for two lengths of vowel following the consonant and three levels of background noise. The stimuli were presented to 30 normal hearing adult participants and the responses were recorded for identification and reaction time task. The results for the identification task revealed that vowel length had a significant effect on the perceptual process with the categorical boundary shifted towards the perception of stop consonant in the presence of long vowel. However, in the presence of noise, the effects of vowel length cues were limited. In such condition, the probable role of multiple acoustic cues in the perception of speech sounds is suggested. On the contrary, no significant effect of vowel length and/or noise was observed in the time taken for the participants to respond to the stimuli. These results were discussed in terms of the role of perceptual normalcy influencing the effect of noise.