Tone 4 Pronounced as Tone 3

• The native speaker's reading of Tone 4 of “質” in the word “性質” is shows dramatic falling trend. Difference between the maximum and minimum pitch values is around 140Hz, from 330Hz to 190Hz.
• For the learners' reading of the same word with Tone 4, the tone contours show falling or dipping trends. Judging from the tone contours, their pronunciation of “質” carries incomplete Tone 3 rather than Tone 4. Differences between the maximum and minimum pitch values are around 80-90Hz. Pitch heights (90-200Hz) are clearly lower than the native speaker's reading.

Suggestions for teachers:

• remind students to keep high pitch value at the beginning of Tone 4 pronunciation
• remind students to decrease pitch height dramatically from the beginning to the end of Tone 4 pronunciation