When human beings perceive speech sounds, they categorize the sounds into one or another phonemic category. The mechanism which is responsible for this phenomenon remains unknown. Is it influenced by listeners' long term language experience or does it reflect some general psychoacoustic aspects of processing? Previous study shows Cantonese level tones are perceived continuously in citation forms . However, they are perceived categorically in the presence of context . The work in  does not provide enough evidence to support the hypothesis of long term language influence. In this study, we compare Mandarin and Cantonese speaker's perception on Cantonese level tones in context, and Cantonese speaker's perception on speech and nonspeech (analogous complex harmonics) in the same context as well. Results show evidence of categorical perception on speech stimuli for Cantonese speakers only. These findings support the hypothesis of long term language influence.
Bibliographic reference. Zheng, Hongying / Tsang, Peter W. M. / Wang, William S. -Y. (2007): "Categorical perception of Cantonese tones in context: a cross-linguistic study", In INTERSPEECH-2007, 2745-2748.