While writing systems and alphabets often attempt to represent the sounds of speech, phoneticians are more concerned with the sounds themselves than the symbols used to represent them. So close is the relationship between them, however, that many dictionaries list the study of the symbols (more accurately semiotics) as a part of phonetic studies . Logographic writing systems typically give much less phonetic information, although it is not necessarily non-existent. For instance, in Chinese characters, a phonetic is a portion of the character that hints at its pronunciation, while the radical gives semantic information. Characters featuring the same phonetic typically have similar pronunciations, but by no means are the pronunciations predictably determined by the phonetic; this is because pronunciations diverged over many centuries while the characters remained the same. Not all Chinese characters are radical-phonetic compounds, but a good majority of them are.
Phonetics has three main branches:
- articulatory phonetics, concerned with the positions and movements of the lips, tongue, vocal tract and folds and other speech organs in producing speech;
- acoustic phonetics, concerned with the properties of the sound waves and how they are received by the inner ear; and
- auditory phonetics, concerned with speech perception, principally how the brain forms perceptual representations of the input it receives.
There are over a hundred different phones recognized as distinctive by the International Phonetic Association (IPA) and transcribed in their International Phonetic Alphabet.
Phonetics was studied as early as 2,500 years ago in ancient India, with Pānini's account of the place and manner of articulation of consonants in his 5th century BCE treatise on Sanskrit. The major Indic alphabets today, except Tamil script, order their consonants according to Pānini's classification.