Acoustic Comparison of Vowel Articulation When Combined with Different Tone Categories in Mandarin

It was found that there existed an interaction between the source (i.e., fundamental frequencies) and the vocal tract filter (i.e., formant frequencies). Previous studies investigated such interaction from a perspective of perception with evidence from Mandarin which uses four tones to distinguish lexical meanings. While few studies examined such interaction from a perspective of production. This study explored differences of formant frequencies in vowel articulation when combined with different fundamental frequency patterns (i.e., tones). We calculated frequencies of the first two formants (i.e., F1, F2) and their distance (i.e., F2-F1) of different vowels with four lexical tones. Results showed that both F1 and F2 values were significantly different when combined with different tones. Moreover, such interaction varied with vowels: high vowels usually presented a contrary correlation pattern compared with other vowels. The finding about the co-variation between formants and fundamental frequencies may help to improve the naturalness of speech synthesis.