- Linguistics : The scientific study of language.
- Language (general) : A type of communication system, commonly used in linguistics, computer science and other fields to refer to different systems, including 'natural language' in humans, programming languages run on computers, and so on. A wider definition of language - what counts as a language and what doesn't - is a difficult philosophical topic, deserving an article in its own right.
- Phonetics : Study of speech sounds and their perception, production, combination, and description.
- Articulatory phonetics : Add brief definition or description
- Acoustic phonetics : Add brief definition or description
- Auditory phonetics : Add brief definition or description
- Phonology : In linguistics, the study of the system used to represent language, including sounds in spoken language and hand movements in sign language.
- Syllable : Unit of organisation in phonology that divides speech sounds or sign language movements into groups to which phonological rules may apply.
- Diphthong : Type of speech sound, articulated through the tongue commencing in the position of a single vowel and moving continuously in the direction of another; e.g. [əʊ] in English low.
- Nasalization : Add brief definition or description
- Voicing (linguistics) : Either the physical production of vibration by the vocal folds as part of articulation, or the potential phonological distinction this allows, i.e. the distinct difference between units such as [b] and [p] in many languages.
- Consonant : Unit of language, defined in phonetics as a speech sound that involves full or partial 'closure' of the mouth, and in phonology as a segment that cannot occupy the nucleus or 'peak' of a syllable.
- Vocal cords : Mucous membranes over the larynx that contribute to the production of sound in mammals.
- Pronunciation : Add brief definition or description
- Spoken language : An example of language produced using some of the articulatory organs, e.g. the mouth, vocal folds or lungs, or intended for production by these organs; alternatively, the entire act of communicating verbally - what people mean or intend, the words they use, their accent, intonation and so on.
- Written language : The communication and representation of a language by means of a writing system.
- Letter (alphabet) : Symbol in an alphabetic script, usually denoting one or more phonemes; for example, in the English alphabet the letter <a> can represent the phoneme /æ/ as in mat and /eɪ/ as in mate.