Downdrift

Lowering of pitch during a sentence

In phonetics, downdrift is the cumulative lowering of pitch in the course of a sentence due to interactions among tones in a tonal language. Downdrift often occurs when the tones in successive syllables are H L H or H L L H. In this case the second high tone tends to be lower than the first. The effect can accumulate so that with each low tone, the pitch of the high tones becomes slightly lower, until the end of the intonational phrase, when the pitch is "reset".

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