Lips are a visible body part at the mouth of humans and many animals. Lips are soft and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, can be an erogenous zone when used in kissing and other acts of intimacy; the upper and lower lips are referred to as the "Labium superius oris" and "Labium inferius oris", respectively. The juncture where the lips meet the surrounding skin of the mouth area is the vermilion border, the reddish area within the borders is called the vermilion zone; the vermilion border of the upper lip is known as the cupid's bow. The fleshy protuberance located in the center of the upper lip is a tubercle known by various terms including the procheilon, the "tuberculum labii superioris", the "labial tubercle"; the vertical groove extending from the procheilon to the nasal septum is called the philtrum. The skin of the lip, with three to five cellular layers, is thin compared to typical face skin, which has up to 16 layers.
With light skin color, the lip skin contains fewer melanocytes. Because of this, the blood vessels appear through the skin of the lips, which leads to their notable red coloring. With darker skin color this effect is less prominent, as in this case the skin of the lips contains more melanin and thus is visually darker; the skin of the lip forms the border between the exterior skin of the face, the interior mucous membrane of the inside of the mouth. The lip skin does not have sweat glands. Therefore, it does not have the usual protection layer of sweat and body oils which keep the skin smooth, inhibit pathogens, regulate warmth. For these reasons, the lips become chapped more easily; the lower lip is formed from a branch of the first pharyngeal arch. The lower lip covers the anterior body of the mandible, it is lowered by the depressor labii inferioris muscle and the orbicularis oris borders it inferiorly. The upper lip covers the anterior surface of the body of the maxilla, its upper half is of usual skin color and has a depression at its center, directly under the nasal septum, called the philtrum, Latin for lower nose, while its lower half is a markedly different, red-colored skin tone more similar to the color of the inside of the mouth, the term vermillion refers to the colored portion of either the upper or lower lip.
It is raised by the levator labii superioris and is connected to the lower lip by the thin lining of the lip itself. Thinning of the vermilion of the upper lip and flattening of the philtrum are two of the facial characteristics of fetal alcohol syndrome, a lifelong disability caused by the mother's consumption of alcohol during pregnancy; the skin of the lips is stratified squamous epithelium. The mucous membrane is represented by a large area in the sensory cortex, is therefore sensitive; the Frenulum Labii Inferioris is the frenulum of the lower lip. The Frenulum Labii Superioris is the frenulum of the upper lip. Trigeminal nerve The infraorbital nerve is a branch of the maxillary branch, it supplies not only the upper lip, but much of the skin of the face between the upper lip and the lower eyelid, except for the bridge of the nose. The mental nerve is a branch of the mandibular branch, it supplies the skin and mucous membrane of labial gingiva anteriorly. The facial artery is one of the six non-terminal branches of the external carotid artery.
This artery supplies both lips by its inferior labial branches. Each of the two branches bifurcate and anastomose with their companion branch from the other terminal; the muscles acting on the lips are considered part of the muscles of facial expression. All muscles of facial expression are derived from the mesoderm of the second pharyngeal arch, are therefore supplied by the nerve of the second pharyngeal arch, the facial nerve; the muscles of facial expression are all specialized members of the panniculus carnosus, which attach to the dermis and so wrinkle, or dimple the overlying skin. Functionally, the muscles of facial expression are arranged in groups around the orbits and mouth; the muscles acting on the lips: Buccinator Orbicularis oris Anchor point for several muscles Modiolus Lip elevation Levator labii superioris levator labii superioris alaeque nasi Levator anguli oris Zygomaticus minor Zygomaticus major Lip depression Risorius Depressor anguli oris Depressor labii inferioris Mentalis Because they have their own muscles and bordering muscles, the lips are movable.
Lips are used for eating functions, like holding food. In addition, lips serve to close the mouth airtight shut, to hold food and drink inside, to keep out unwanted objects. Through making a narrow funnel with the lips, the suction of the mouth is increased; this suction is essential for babies to breast feed. Lips can be used to suck in other contexts, such as sucking on a straw to drink liquids; the lips serve for creating different sounds—mainly labial and labiodental consonant sounds as well as vowel rounding—and thus are an important part of the speech apparatus. The lips enable whistling and the performing of wind instruments such as the trumpet, clarinet and saxophone. People who have hearing loss may unconsciously or consciously lip read to understand speech without needing to perceive the actual sounds; the lip reacts as part of the tactile senses. Lips are sensitive to touch and cold, it is therefore
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers. Turbulence is observed in everyday phenomena such as surf, fast flowing rivers, billowing storm clouds, or smoke from a chimney, most fluid flows occurring in nature or created in engineering applications are turbulent. Turbulence is caused by excessive kinetic energy in parts of a fluid flow, which overcomes the damping effect of the fluid's viscosity. For this reason turbulence is realized in low viscosity fluids. In general terms, in turbulent flow, unsteady vortices appear of many sizes which interact with each other drag due to friction effects increases; this increases the energy needed to pump fluid through a pipe. Turbulence can be exploited, for example, by devices such as aerodynamic spoilers on aircraft that "spoil" the laminar flow to increase drag and reduce lift.
The onset of turbulence can be predicted by the dimensionless Reynolds number, the ratio of kinetic energy to viscous damping in a fluid flow. However, turbulence has long resisted detailed physical analysis, the interactions within turbulence create a complex phenomenon. Richard Feynman has described turbulence as the most important unsolved problem in classical physics. Smoke rising from a cigarette. For the first few centimeters, the smoke is laminar; the smoke plume becomes turbulent as its Reynolds number increases with increases in flow velocity and characteristic lengthscale. Flow over a golf ball. If the golf ball were smooth, the boundary layer flow over the front of the sphere would be laminar at typical conditions. However, the boundary layer would separate early, as the pressure gradient switched from favorable to unfavorable, creating a large region of low pressure behind the ball that creates high form drag. To prevent this, the surface is dimpled to promote turbulence; this results in higher skin friction, but it moves the point of boundary layer separation further along, resulting in lower drag.
Clear-air turbulence experienced during airplane flight, as well as poor astronomical seeing. Most of the terrestrial atmospheric circulation; the oceanic and atmospheric mixed intense oceanic currents. The flow conditions in many industrial equipment and machines; the external flow over all kinds of vehicles such as cars, airplanes and submarines. The motions of matter in stellar atmospheres. A jet exhausting from a nozzle into a quiescent fluid; as the flow emerges into this external fluid, shear layers originating at the lips of the nozzle are created. These layers separate the fast moving jet from the external fluid, at a certain critical Reynolds number they become unstable and break down to turbulence. Biologically generated. Snow fences work by inducing turbulence in the wind, forcing it to drop much of its snow load near the fence. Bridge supports in water. In the late summer and fall, when river flow is slow, water flows smoothly around the support legs. In the spring, when the flow is faster, a higher Reynolds number is associated with the flow.
The flow may start off laminar but is separated from the leg and becomes turbulent. In many geophysical flows, the flow turbulence is dominated by the coherent structures and turbulent events. A turbulent event is a series of turbulent fluctuations that contain more energy than the average flow turbulence; the turbulent events are associated with coherent flow structures such as eddies and turbulent bursting, they play a critical role in terms of sediment scour and transport in rivers as well as contaminant mixing and dispersion in rivers and estuaries, in the atmosphere. In the medical field of cardiology, a stethoscope is used to detect heart sounds and bruits, which are due to turbulent blood flow. In normal individuals, heart sounds are a product of turbulent flow as heart valves close. However, in some conditions turbulent flow can be audible due to other reasons, some of them pathological. For example, in advanced atherosclerosis, bruits can be heard in some vessels that have been narrowed by the disease process.
Turbulence in porous media became a debated subject. Turbulence is characterized by the following features: Irregularity Turbulent flows are always irregular. For this reason, turbulence problems are treated statistically rather than deterministically. Turbulent flow is chaotic. However, not all chaotic flows are turbulent. Diffusivity The available supply of energy in turbulent flows tends to accelerate the homogenization of fluid mixtures; the characteristic, responsible for the enhanced mixing and increased rates of mass and energy transports in a flow is called "diffusivity". Turbulent diffusion is described by a turbulent diffusion coefficient; this turbulent diffusion coefficient is defined in a phenomenological sense, by analogy with the molecular diffusivities, but it does not have a true physical meaning, being dependent on the flow conditions, not a property of the fluid itself. In addition, the turbulent diffusivity concept assumes a con
International Phonetic Alphabet
The International Phonetic Alphabet is an alphabetic system of phonetic notation based on the Latin alphabet. It was devised by the International Phonetic Association in the late 19th century as a standardized representation of the sounds of spoken language; the IPA is used by lexicographers, foreign language students and teachers, speech-language pathologists, actors, constructed language creators and translators. The IPA is designed to represent only those qualities of speech that are part of oral language: phones, phonemes and the separation of words and syllables. To represent additional qualities of speech, such as tooth gnashing and sounds made with a cleft lip and cleft palate, an extended set of symbols, the extensions to the International Phonetic Alphabet, may be used. IPA symbols are composed of one or more elements of two basic types and diacritics. For example, the sound of the English letter ⟨t⟩ may be transcribed in IPA with a single letter, or with a letter plus diacritics, depending on how precise one wishes to be.
Slashes are used to signal broad or phonemic transcription. Letters or diacritics are added, removed or modified by the International Phonetic Association; as of the most recent change in 2005, there are 107 letters, 52 diacritics and four prosodic marks in the IPA. These are shown in the current IPA chart, posted below in this article and at the website of the IPA. In 1886, a group of French and British language teachers, led by the French linguist Paul Passy, formed what would come to be known from 1897 onwards as the International Phonetic Association, their original alphabet was based on a spelling reform for English known as the Romic alphabet, but in order to make it usable for other languages, the values of the symbols were allowed to vary from language to language. For example, the sound was represented with the letter ⟨c⟩ in English, but with the digraph ⟨ch⟩ in French. However, in 1888, the alphabet was revised so as to be uniform across languages, thus providing the base for all future revisions.
The idea of making the IPA was first suggested by Otto Jespersen in a letter to Paul Passy. It was developed by Alexander John Ellis, Henry Sweet, Daniel Jones, Passy. Since its creation, the IPA has undergone a number of revisions. After revisions and expansions from the 1890s to the 1940s, the IPA remained unchanged until the Kiel Convention in 1989. A minor revision took place in 1993 with the addition of four letters for mid central vowels and the removal of letters for voiceless implosives; the alphabet was last revised in May 2005 with the addition of a letter for a labiodental flap. Apart from the addition and removal of symbols, changes to the IPA have consisted of renaming symbols and categories and in modifying typefaces. Extensions to the International Phonetic Alphabet for speech pathology were created in 1990 and adopted by the International Clinical Phonetics and Linguistics Association in 1994; the general principle of the IPA is to provide one letter for each distinctive sound, although this practice is not followed if the sound itself is complex.
This means that: It does not use combinations of letters to represent single sounds, the way English does with ⟨sh⟩, ⟨th⟩ and ⟨ng⟩, or single letters to represent multiple sounds the way ⟨x⟩ represents /ks/ or /ɡz/ in English. There are no letters that have context-dependent sound values, as do "hard" and "soft" ⟨c⟩ or ⟨g⟩ in several European languages; the IPA does not have separate letters for two sounds if no known language makes a distinction between them, a property known as "selectiveness". Among the symbols of the IPA, 107 letters represent consonants and vowels, 31 diacritics are used to modify these, 19 additional signs indicate suprasegmental qualities such as length, tone and intonation; these are organized into a chart. The letters chosen for the IPA are meant to harmonize with the Latin alphabet. For this reason, most letters modifications thereof; some letters are neither: for example, the letter denoting the glottal stop, ⟨ʔ⟩, has the form of a dotless question mark, derives from an apostrophe.
A few letters, such as that of the voiced pharyngeal fricative, ⟨ʕ⟩, were inspired by other writing systems. Despite its preference for harmonizing with the Latin script, the International Phonetic Association has admitted other letters. For example, before 1989, the IPA letters for click consonants were ⟨ʘ⟩, ⟨ʇ⟩, ⟨ʗ⟩, ⟨ʖ⟩, all of which were derived either from existing IPA letters, or from Latin and Greek letters. However, except for ⟨ʘ⟩, none of these letters were used among Khoisanists or Bantuists, as a result they were replaced by the more widespread symbols ⟨ʘ⟩, ⟨ǀ⟩, ⟨ǃ⟩, ⟨ǂ⟩, ⟨ǁ⟩ at the IPA Kiel Convention in 1989. Although the IPA diacritics are featural, there is little systemicity in the letter forms. A retroflex articulation is indicated with a right-swinging tail, as in ⟨ɖ ʂ ɳ⟩, implosion by a top hook, ⟨ɓ ɗ ɠ⟩, but other pseudo-featural elements are due to haphazard derivation and coincidence. For example, all nasal consonants but uvular ⟨ɴ⟩ are based on the form ⟨n⟩: ⟨m ɱ n ɳ ɲ ŋ⟩.
However, the similarity between ⟨m⟩ and ⟨n⟩ is a historical accident. Some of the new letters were ordinary Latin letters tu
The Korean alphabet, known as Hangul, has been used to write the Korean language since its creation in the 15th century by King Sejong the Great. It may be written as Hangeul following the standard Romanization, it is the official writing system of Korea, both North. It is a co-official writing system in the Yanbian Korean Autonomous Prefecture and Changbai Korean Autonomous County in Jilin Province, China, it is sometimes used to write the Cia-Cia language spoken near the town of Indonesia. The Hangul alphabet consisted of 28 letters with 17 consonant letters and 11 vowel letters when it was created; as four became obsolete, the modern Hangul consists of total 24 letters with 14 consonant letters and 10 vowel letters. In North Korea the total is counted 40, it consists of 19 consonant letters and 21 vowel letters as it additionally includes 5 tense consonants and 20. The Korean letters are written in syllabic blocks with each alphabetic letter placed vertically and horizontally into a square dimension.
For example, the Korean word for "honeybee" is written 꿀벌, not ㄲㅜㄹㅂㅓㄹ. As it combines the features of alphabetic and syllabic writing systems, it has been described as an "alphabetic syllabary" by some linguists; as in traditional Chinese writing, Korean texts were traditionally written top to bottom, right to left, are still written this way for stylistic purposes. Today, it is written from left to right with spaces between words and western-style punctuation; some linguists consider it among the most phonologically faithful writing systems in use today. One interesting feature of Hangul is that the shapes of its consonants mimic the shapes of the speaker's mouth when pronouncing each consonant; the Korean alphabet was called Hunminjeong'eum, after the document that introduced the script to the Korean people in 1446. The Korean alphabet is called hangeul, a name coined by Korean linguist Ju Si-gyeong in 1912; the name combines the ancient Korean word han, meaning "great", geul, meaning "script".
The word han is used to refer to Korea in general, so the name means "Korean script". It has been romanized in multiple ways: Hangeul or han-geul in the Revised Romanization of Korean, which the South Korean government uses in English publications and encourages for all purposes. Han'gŭl in the McCune–Reischauer system, is capitalized and rendered without the diacritics when used as an English word, Hangul, as it appears in many English dictionaries. Hānkul in the Yale romanization, a system recommended for technical linguistic studies. In North Korea it is called Chosŏn'gŭl after Chosŏn, the North Korean name for Korea after the old name of Korea; the McCune–Reischauer system is used there. Until the mid-20th century, the Korean elite preferred to write using Chinese characters called Hanja, they referred to Hanja as jinseo or "true letters". Some accounts say the elite referred to the Korean alphabet derisively as'amkeul meaning "women's script", and'ahaetgeul meaning "children's script", though there is no written evidence of this.
Supporters of the Korean alphabet referred to it as jeong'eum meaning "correct pronunciation", gukmun meaning "national script", eonmun meaning "vernacular script". Before the creation of the new Korean alphabet, Koreans wrote using Classical Chinese alongside native phonetic writing systems that predate the modern Korean alphabet by hundreds of years, including Idu script, Hyangchal and Gakpil. However, due to fundamental differences between the Korean and Chinese languages, the large number of characters, many lower class Koreans were illiterate. To promote literacy among the common people, the fourth king of the Joseon dynasty, Sejong the Great created and promulgated a new alphabet; the Korean alphabet was designed so that people with little education could learn to write. A popular saying about the alphabet is, "A wise man can acquaint himself with them before the morning is over; the project was completed in late December 1443 or January 1444, described in 1446 in a document titled Hunminjeong'eum, after which the alphabet itself was named.
The publication date of the Hunminjeongeum, October 9, became Hangul Day in South Korea. Its North Korean equivalent, Chosŏn'gŭl Day, is on January 15. Another document published in 1446 and titled Hunminjeong'eum Haerye was discovered in 1940; this document explains that the design of the consonant letters is based on articulatory phonetics and the design of the vowel letters are based on the principles of yin and yang and vowel harmony. The Korean alphabet faced opposition in the 1440s by the literary elite, including politician Choe Manri and other Korean Confucian scholars, they believed. They saw the circulation of the Korean alphabet as a threat to their status. However, the Korean alphabet entered popular culture as King Sejong had intended, used by women and writers of popular fiction. King Yeonsangun banned the study and publication of the Korean alphabet in 1504, after a document criticizing the king entered the public. King Jungjong abolished the Ministry of Eonmun, a governmental institution related to Hangul research, in 1506.
The late 16th century, saw a revival of the Korean alphabet as gasa and sijo poetry flourished. In the 17th century, the Korean alphabet novels became a major genre. However, the use of the Korea
German orthography is the orthography used in writing the German language, phonemic. However, it shows many instances of spellings that are historic or analogous to other spellings rather than phonemic; the pronunciation of every word can be derived from its spelling once the spelling rules are known, but the opposite is not the case. Today, German orthography is regulated by the Rat für deutsche Rechtschreibung, composed of representatives from most German-speaking countries; the modern German alphabet consists of the twenty-six letters of the ISO basic Latin alphabet plus four special letters. ^ In the spelling alphabet, for ⟨ch⟩, Charlotte is used. For the trigraph ⟨sch⟩, Schule is used. German uses three letter-diacritic combinations using the umlaut and one ligature which are considered distinct letters of the alphabet; the capital ẞ was declared an official letter of the German alphabet on 29 June 2017. In the past, long s was used as well, as in many other European languages. While the Council for German Orthography considers Ä/ä, Ö/ö, Ü/ü, ẞ/ß distinct letters, disagreement on how to categorize and count them has led to a dispute over the exact number of letters the German alphabet has, the number ranging between 26 and 30.
The diacritic letters ä, ö and ü are used to indicate the presence of umlauts. Before the introduction of the printing press, frontalization was indicated by placing an e after the back vowel to be modified, but German printers developed the space-saving typographical convention of replacing the full e with a small version placed above the vowel to be modified. In German Kurrent writing, the superscripted e was simplified to two vertical dashes, which have further been reduced to dots in both handwriting and German typesetting. Although the two dots of umlaut look like those in the diaeresis, the two have different origins and functions; when it is not possible to use the umlauts the characters Ä, Ö, Ü, ä, ö, ü should be transcribed as Ae, Oe, Ue, ae, oe, ue following the earlier postvocalic-e convention. However, such transcription should be avoided if possible with names. Names exist in different variants, such as "Müller" and "Mueller", with such transcriptions in use one could not work out the correct spelling of the name.
Automatic back-transcribing is not only wrong for names. Consider, for example, das neue Buch; this should never be changed to das neü Buch, as the second e is separate from the u and does not belong in the same syllable. The word neü does not exist in German. Furthermore, in northern and western Germany, there are family names and place names in which e lengthens the preceding vowel, as in the former Dutch orthography, such as Straelen, pronounced with a long a, not an ä. Similar cases are Bernkastel-Kues. In proper names and ethnonyms, there may appear a rare ë and ï, which are not letters with an umlaut, but a diaeresis, used as in French to distinguish what could be a digraph, for example, ai in Karaïmen, eu in Alëuten, ie in Ferdinand Piëch, oe in Clemens von Loë and Bernhard Hoëcker, ue in Niuë. A diaeresis may be used in some well-known names, i.e.: Italiën. To separate the au diphthong, as well as some others, which are graphically composed of umlaut-holding letters, the acute accent is sometimes used.
Swiss typewriters and computer keyboards do not allow easy input of uppercase letters with umlauts because their positions are taken by the most frequent French diacritics. Uppercase umlauts were dropped. Geographical names in particular are supposed to be written with A, O, U plus e except "Österreich"; the omission can cause some inconvenience since the first letter of every noun is capitalized in German. Unlike in Hungarian, the exact shape of the umlaut diacritics – when handwritten – is not important, because they are the only ones in the language, they will be understood whether they look like dots, acute accents, vertical bars, a horizontal bar, a breve, a tiny N or e, a tilde, such variations are used in stylized writing. In the past, the breve was traditionally used in some scripts to distinguish a u from an n, as was the ring. In rare cases the n was underlined; the breved u was common in some Kurrent-derived handwritings. The eszett or scharfes S represents; the German spelling reform of 1996 somewhat reduced usage of this letter in Austria.
It is not used in Liechtenstein. As the ß derives from a ligature of lowercase letters, it is used in the middle or the end of a word; the proper transcription when it cannot be used, is ss. This transcription can give rise to ambiguities, albeit rarely. For all caps usage, an uppercase ß was added to the German alphabet in 2017. In 2008, it was included in Unicode 5.1 as U+1E9E, since 2010
Manner of articulation
In articulatory phonetics, the manner of articulation is the configuration and interaction of the articulators when making a speech sound. One parameter of manner is stricture, that is, how the speech organs approach one another. Others include those involved in the r-like sounds, the sibilancy of fricatives; the concept of manner is used in the discussion of consonants, although the movement of the articulators will greatly alter the resonant properties of the vocal tract, thereby changing the formant structure of speech sounds, crucial for the identification of vowels. For consonants, the place of articulation and the degree of phonation of voicing are considered separately from manner, as being independent parameters. Homorganic consonants, which have the same place of articulation, may have different manners of articulation. Nasality and laterality are included in manner, but some phoneticians, such as Peter Ladefoged, consider them to be independent. Manners of articulation with substantial obstruction of the airflow are called obstruents.
These are prototypically voiceless, but voiced obstruents are common as well. Manners without such obstruction are called sonorants. Voiceless sonorants are uncommon, but are found in Welsh and Classical Greek, in Standard Tibetan, the "wh" in those dialects of English that distinguish "which" from "witch". Sonorants may be called resonants, some linguists prefer that term, restricting the word'sonorant' to non-vocoid resonants. Another common distinction is between continuants. From greatest to least stricture, speech sounds may be classified along a cline as stop consonants, fricative consonants and vowels. Affricates behave as if they were intermediate between stops and fricatives, but phonetically they are sequences of a stop and fricative. Over time, sounds in a language may move along this cline toward less stricture in a process called lenition, or towards more stricture in a process called fortition. Sibilants are distinguished from other fricatives by the shape of the tongue and how the airflow is directed over the teeth.
Fricatives at coronal places of articulation may be sibilant or non-sibilant, sibilants being the more common. Flaps are similar to brief stops. However, their articulation and behavior are distinct enough to be considered a separate manner, rather than just length; the main articulatory difference between flaps and stops is that, due to the greater length of stops compared to flaps, a build-up of air pressure occurs behind a stop which does not occur behind a flap. This means that when the stop is released, there is a burst of air as the pressure is relieved, while for flaps there is no such burst. Trills involve the vibration of one of the speech organs. Since trilling is a separate parameter from stricture, the two may be combined. Increasing the stricture of a typical trill results in a trilled fricative. Trilled affricates are known. Nasal airflow may be added as an independent parameter to any speech sound, it is most found in nasal occlusives and nasal vowels, but nasalized fricatives and approximants are found.
When a sound is not nasal, it is called oral. Laterality is the release of airflow at the side of the tongue; this can be combined with other manners, resulting in lateral approximants, lateral flaps, lateral fricatives and affricates. Stop, an oral occlusive, where there is occlusion of the oral vocal tract, no nasal air flow, so the air flow stops completely. Examples include English /p t k/ and /b d ɡ/. If the consonant is voiced, the voicing is the only sound made during occlusion. What we hear as a /p/ or /k/ is the effect that the onset of the occlusion has on the preceding vowel, as well as the release burst and its effect on the following vowel; the shape and position of the tongue determine the resonant cavity that gives different stops their characteristic sounds. All languages have stops. Nasal, a nasal occlusive, where there is occlusion of the oral tract, but air passes through the nose; the shape and position of the tongue determine the resonant cavity that gives different nasals their characteristic sounds.
Examples include English /m, n/. Nearly all languages have nasals, the only exceptions being in the area of Puget Sound and a single language on Bougainville Island. Fricative, sometimes called spirant, where there is continuous frication at the place of articulation. Examples include etc.. Most languages have fricatives, though many have only an /s/. However, the Indigenous Australian languages are completely devoid of fricatives of any kind. Sibilants are a type of fricative where the airflow is guided by a groove in the tongue toward the teeth, creating a high-pitched and distinctive sound; these are by far the most common fricatives. Fricatives at coronal places of articulation are though not always, sibilants. English sibilants include /s/ and /z/. Lateral fricatives are a rare type of fricative, where the frication occurs on one or both sides of the edge of th
The Greek alphabet has been used to write the Greek language since the late ninth or early eighth century BC. It is derived from the earlier Phoenician alphabet, was the first alphabetic script to have distinct letters for vowels as well as consonants. In Archaic and early Classical times, the Greek alphabet existed in many different local variants, but, by the end of the fourth century BC, the Eucleidean alphabet, with twenty-four letters, ordered from alpha to omega, had become standard and it is this version, still used to write Greek today; these twenty-four letters are: Α α, Β β, Γ γ, Δ δ, Ε ε, Ζ ζ, Η η, Θ θ, Ι ι, Κ κ, Λ λ, Μ μ, Ν ν, Ξ ξ, Ο ο, Π π, Ρ ρ, Σ σ/ς, Τ τ, Υ υ, Φ φ, Χ χ, Ψ ψ, Ω ω. The Greek alphabet is the ancestor of the Cyrillic scripts. Like Latin and Cyrillic, Greek had only a single form of each letter. Sound values and conventional transcriptions for some of the letters differ between Ancient and Modern Greek usage, because the pronunciation of Greek has changed between the fifth century BC and today.
Modern and Ancient Greek use different diacritics. Apart from its use in writing the Greek language, in both its ancient and its modern forms, the Greek alphabet today serves as a source of technical symbols and labels in many domains of mathematics and other fields. In both Ancient and Modern Greek, the letters of the Greek alphabet have stable and consistent symbol-to-sound mappings, making pronunciation of words predictable. Ancient Greek spelling was near-phonemic. For a number of letters, sound values differ between Ancient and Modern Greek, because their pronunciation has followed a set of systematic phonological shifts that affected the language in its post-classical stages. Examples Notes Among consonant letters, all letters that denoted voiced plosive consonants and aspirated plosives in Ancient Greek stand for corresponding fricative sounds in Modern Greek; the correspondences are as follows: Among the vowel symbols, Modern Greek sound values reflect the radical simplification of the vowel system of post-classical Greek, merging multiple distinct vowel phonemes into a much smaller number.
This leads to several groups of vowel letters denoting identical sounds today. Modern Greek orthography remains true to the historical spellings in most of these cases; as a consequence, the spellings of words in Modern Greek are not predictable from the pronunciation alone, while the reverse mapping, from spelling to pronunciation, is regular and predictable. The following vowel letters and digraphs are involved in the mergers: Modern Greek speakers use the same, modern symbol–sound mappings in reading Greek of all historical stages. In other countries, students of Ancient Greek may use a variety of conventional approximations of the historical sound system in pronouncing Ancient Greek. Several letter combinations have special conventional sound values different from those of their single components. Among them are several digraphs of vowel letters that represented diphthongs but are now monophthongized. In addition to the four mentioned above, there is ⟨ηι, ωι⟩, ⟨ου⟩, pronounced /u/; the Ancient Greek diphthongs ⟨αυ⟩, ⟨ευ⟩ and ⟨ηυ⟩ are pronounced, in Modern Greek.
In some environments, they are devoiced to, respectively. The Modern Greek consonant combinations ⟨μπ⟩ and ⟨ντ⟩ stand for and respectively. In addition, both in Ancient and Modern Greek, the letter ⟨γ⟩, before another velar consonant, stands for the velar nasal. In analogy to ⟨μπ⟩ and ⟨ντ⟩, ⟨γκ⟩ is used to stand for. There are the combinations ⟨γχ⟩ and ⟨γξ⟩. In the polytonic orthography traditionally used for ancient Greek, the stressed vowel of each word carries one of three accent marks: either the acute accent, the grave accent, or the circumflex accent; these signs were designed to mark different forms of the phonological pitch accent in Ancient Greek. By the time their use became conventional and obligatory in Greek writing, in late antiquity, pitch accent was evolving into a single stress accent, thus the three signs have not corresponded to a phonological distinction in actual speech since. In addition to the accent marks, every word-initial vowel must carry either of two so-called "breathing marks": the rough breathing, marking an /h/ sound at the beginning of a word, or the smooth breathing, marking its absence.
The letter rho, although not a vowel carries a rough breathing in word-initial position. If a rho was geminated within a word, the first ρ always had the smooth breathing and the second the rough breathing leading to the transliteration rrh; the vowel letters ⟨α, η, ω⟩ carry an additional diacritic in certain words, the so-called iota subscript, which has the shape of a small vertical stroke or a miniature ⟨ι⟩ below the letter. This iota represents the former offglide of what were long diphthongs, ⟨ᾱι, ηι, ωι⟩, which became monophthongized during antiquity. Another diacritic used in Greek is the diaeresis; this system of diacritics was first developed by the scholar Aristophanes of Byzantium, who worked at the Musaeum in Alexandria during the third century BC. Aristophanes of Byzantium was the first to divide poems into lines, rather than writing them like prose, introduced a series of signs for textual criticism. In 1982, a new, simplif