The branch of linguistics that studies speech sounds is phonetics. It examines the physical production, transmission, and perception of sounds used in human speech, from the movement of the vocal organs to the sound waves reaching a listener.
Phonetics is commonly divided into three areas. Articulatory phonetics studies how the tongue, lips, vocal cords, and other parts of the speech apparatus create sounds. Acoustic phonetics analyzes their physical properties as sound waves. Auditory phonetics investigates how listeners perceive and interpret those sounds.
Phonetics differs from phonology, although the two fields are closely related. Phonetics focuses on the physical details of actual sounds, called phones. Phonology studies how a particular language organizes sounds into an abstract system, including phonemes that can distinguish meaning, such as the sounds represented by the initial letters in “pat” and “bat.”
Linguists describe consonants using features such as place of articulation, manner of articulation, and voicing. Vowels are often described by tongue height, tongue position, and lip rounding. The International Phonetic Alphabet provides symbols for comparing speech sounds across languages.