Fundamental Frequency Contours，Turning Points andΔ...
As shown in Fig.11.1 below，tone 1 is high and relatively level over most of the tone’s duration.Tone 2 exhibits a rise for much of its duration，the onset of the rise occurring in the middle region of the F0 range and ending at a point approaching the F0 height of tone 1.Tone 3 contour occupies the lowest region of the F0 range overall，although extending at least to the midpoint of the range by the offset.Tone 3 onset is variable and can be close in frequency to that of tone 2.Tone 4 begins high and falls to the bottom of the range.A turning point is the point in time at which the contour changes from falling to rising andΔF0 is the F0 change from the onset of the tone to a turning point(Moore and Jongman，1997).Fig.11.1 follows Yuanren Zhao’s tone pitch range model and divides the F0 values into five levels:level 5 is the highest at the top and level 1 is the lowest at the bottom.Tone 1 is5-5-5，tone 2 is3-5，tone 3 is 2-1-4 and tone 4 is5-1.Some scholars also recommended teaching tone 3 as2-1，which would be easier for beginners.
Fig.11.1 Pitch contours of Mandarin tones