Phonetics is the branch of linguistics that studies sound emissions in articulated speech, the only faculty that humans do not share with any other animal creature.
Human languages can produce a vast number of different sounds, which are catalogued in the International Phonetic Alphabet (IPA), devised by the International Phonetic Association as a standardised representation of the sounds of oral languages.
Currently it contains 107 letters, 52 diacritics, and four prosodic marks: 163 symbols can thus represent all the sound of the world's human languages, or most of them anyway.
Some of these often obscure symbols can be seen in square brackets or slashes following a dictionary word and preceding its meaning. For instance, a dictionary entry for man may look like:
/mæn/ (Oxford Advanced Learner's Dictionary, UK)
/man/ (Merriam-Webster Dictionary, USA)
Voice emissions are analysed by phoneticians in terms of:
How they are produced (manner and degree of articulation)
Where they are produced in the vocal tract (place of articulation)
The "articulators" are the speech organs such as the tongue, lips, and palate.
How language sounds are rendered in writing, for example in some scripts and alphabets, is discussed elsewhere.
Affricate consonants (sequences of a stop and fricative)
Nasal consonants (a.k.a. nasal occlusives)
Liquid consonants (partially blocked airflow)
Glide consonants (a.k.a. semivowels)
Sounds pronounced with an open vocal tract, so that the tongue does not touch the lips, teeth, or roof of the mouth - there is no build-up of air pressure at any point above the glottis.
Manner of articulation of consonants
Degree of Phonation or Voicing
The phonatory process, or voicing, occurs when air is expelled from the lungs through the glottis, creating a pressure drop across the larynx. When this drop becomes sufficiently large, the vocal folds start to oscillate. The vocal folds will not oscillate if they are not sufficiently close to one another, are not under sufficient tension or under too much tension, or if the pressure drop across the larynx is not sufficiently large.
In linguistics, a sound is called voiceless if there is no phonation during its occurrence. In speech, voiceless phones are associated with vocal folds that are elongated, highly tensed, and placed laterally (abducted) when compared to vocal folds during phonation.
In English, every voiced fricative (i.e. S, Z, TH) has a corresponding voiceless one.
Over time, sounds in a language may move toward less stricture in a process called lenition ("sweetening") or towards more stricture in a process called fortition ("hardening").
The human vocal tract
Place of Articulation
WHERE sounds are produced. They are classified as:
Places of articulation in the human vocal tract
Some Phonetic Oddities
The Slavic Щ Sound
The sibilant+occlusive Щ (sh-ch) sound is frequent in many Slavic languages but absent in most other languages except, curiously, in some Northern Italian dialects like Milanese, Genoese, Venetian.
No double consonants except R (LL is a single, independent consonant like Portuguese LH), its fricatives (S, Z) are voiceless only.
On La Gomera in the Canary Islands a whistled register of Spanish is used. to communicate across the deep ravines and narrow valleys that radiate through the island. It enables messages to be exchanged over a distance of up to 5 kilometres.
Khoisan languages, all but two are indigenous to southern Africa, have click consonants, as exemplified by Miriam Makeba in her Click Song. .
To a lesser extent they also occur in three neighbouring groups of Bantu languages.
The only non-African language known to have clicks as regular speech sounds is Damin, a ritual code used by speakers of Lardil on Mornington Island, Australia.