Pitch is how humans perceive frequency, which is a measure of vocal fold vibration. Frequency is often measured in hertz (Hz) which is equal to one sound cycle (or vibration) per second. A greater number of cycles per second correlates with more Hz and higher pitch; fewer cycles results in lower pitch. Pitch is affected by the physical stature of the speaker which often determines the size of the vocal folds and the length of the vocal tract.
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- Crystal, David. (1997) A Dictionary of Linguistics and Phonetics. Oxford, UK: Blackwell.
- Ladefoged, D. (2010) A Course in Phonetics. 6th Edition. Wadsworth Publishing.