5th International Conference on Spoken Language Processing
One of the often recurring results in categorical perception research is the difference between the perception of consonants, mainly stop consonants, and vowels. Stop consonants are said to be categorically perceived, whereas the perception of vowels is often called continuous. The difference in perception between stop consonants and vowels could be due to the difference in coding between these speech sounds.
Bibliographic reference. Gerrits, Ellen / Schouten, Bert (1998): "Categorical perception of vowels", In ICSLP-1998, paper 0265.