Representation and processing of pitch in tonal languages
PhD student: Jessie Nixon
Supervisors: Yiya Chen and Niels O. Schiller
I work within the ERC project The representation and processing of pitch in tonal languages. My research focuses on how native speakers of Beijing Mandarin store lexical tone in the brain and access it during speech. Beijing Mandarin has four lexical tones. These tones distinguish between words in the same way that 'phonemes' (approximately letter-sized units of sound) do in other languages (e.g. cat versus bat in English; mao1 'cat' verses mao2 'reed' in Chinese).
I am investigating how abstract or specific our representations of speech sounds are. When we retrieve words from memory, how much detail is retained in our phonological (sound) representations of these words? Although we may not be aware of it, there is a huge amount of variation in the pronunciation of even a single word, due to factors such as speech rate, repetition, familiarity and context. This is also true of Mandarin tones. For example, the '3rd tone' is usually low; but when two 3rd tones occur together, the first has a rising contour.
So, how do speakers store this variability? Many early accounts proposed that words were stored as series of abstract 'phonemes'. This would suggest that Mandarin tones would be stored and processed in abstract representations of one of the four lexical tones. However, my latest experiments have shown that seeing printed words activates detailed acoustic representations of tone. Ongoing experiments will examine whether there is also an abstract level of representation. In addition, electrophysiological methods will be used to investigate exactly when each of the various levels of representation is activated.