Acoustic Space of Vowels with Different Tones: Case of Thai Language

Thai language has five tones in phonemic contrast which makes it a good object to study if tonal contours or levels have any influence on spectral properties of vowels. The present study takes into account each one of the eighteen vowels of Thai with five different phonemic tones. PRAAT and Wave surfer are used in order to arrive at the formant values and pitch, levels and contours in terms of Fo. F1 plotted against F2-F1 gives us the acoustic space of all the peripheral vowels. Acoustic space of vowels with different tones shows interesting results: Rising tone and falling rising tonal contour both seems to have a significant influence on acoustic space.