What is the study of the sounds of human speech called?

The study of the sounds of human speech is called phonetics. It examines how sounds are produced by the vocal tract, transmitted as sound waves, and perceived by listeners.

Phonetics is commonly divided into articulatory, acoustic, and auditory phonetics. Articulatory phonetics studies movements of the tongue, lips, vocal folds, and other speech organs; acoustic phonetics measures properties such as frequency and duration; auditory phonetics investigates how the brain perceives speech.

A common mix-up is phonology, which studies how a particular language organizes sounds into a system of contrasts. For example, phonetics can describe the physical difference between sounds, while phonology asks whether that difference changes meaning in a language. Syntax concerns sentence structure, and morphology concerns word structure.

Modern phonetic transcription often uses the International Phonetic Alphabet, whose symbols represent speech sounds across languages rather than ordinary spelling.