Phonetics
Phonetics is the branch of linguistics concerned with the physical sounds of human speech — how they are produced, transmitted, and perceived. It treats speech sounds as concrete physical events, independent of the language-specific systems that organise them.
The three branches
The field divides into three traditional sub-disciplines defined by the stage of the speech chain they investigate. Articulatory Phonetics studies sound production by the Vocal Tract — airstream mechanisms, the action of articulators, place and manner of articulation, voicing. Acoustic Phonetics studies the physical properties of the speech signal as it travels through air — frequency, amplitude, duration, formant structure — typically using waveforms and spectrograms. Auditory Phonetics studies how listeners receive and process the signal, from cochlear mechanics to higher-level perceptual categorisation. The three together describe the full speaker–signal–listener loop.
Phonetics versus phonology
Phonetics describes sounds as physical events; Phonology describes how a particular language organises sounds into a system of contrasts and patterns. The phonetic difference between aspirated [pʰ] and unaspirated [p] exists in every language, but only some languages (Hindi, Thai) treat it as phonemic. Roach (2009) and Ladefoged & Johnson (2014) treat the distinction as one of focus rather than substance: a phonetician asks what is articulated, a phonologist asks what counts.
Tools and notation
The discipline relies on the International Phonetic Alphabet for transcription. Modern phonetic research uses acoustic analysis software (Praat, ELAN), articulatory imaging (ultrasound, MRI, electromagnetic articulography), and laboratory perception experiments. In ELT, phonetic description grounds Pronunciation teaching by giving teachers and learners a precise vocabulary for the targets being taught.
References
- Ladefoged, P., & Johnson, K. (2014). A Course in Phonetics (7th ed.). Cengage Learning.
- Roach, P. (2009). English Phonetics and Phonology: A Practical Course (4th ed.). Cambridge University Press.
- International Phonetic Association (1999). Handbook of the International Phonetic Association. Cambridge University Press.