A standard language or standard variety may be defined either as a language variety used by a population for public purposes or as a variety that has undergone standardization. Typically, varieties that become standardized are the local dialects spoken in the centers of commerce and government, where a need arises for a variety that will serve more than local needs. Standardization typically involves a fixed orthography, codification in authoritative grammars and dictionaries and public acceptance of these standards. A standard written language is sometimes termed by the German word Schriftsprache.
A pluricentric language has multiple interacting standard varieties. Examples include English, French, Portuguese, German, Korean, Spanish, Swedish, Armenian and Chinese. Monocentric languages, such as Russian and Japanese, have only one standardized version.
A standard variety is developed from a group of related varieties. This may be done by elevating a single variety, such as the local variety of a center of government or culture. Alternatively, a new variety may be defined as a selection of features from existing varieties. A fixed orthography is typically created for writing the variety. It may be codified in normative dictionaries and grammars, or by an agreed collection of exemplary texts. Whether these dictionaries and grammars are created by private individuals (like Webster's Dictionary) or by state institutions, they become standard if they are treated as authorities for correcting language. A fixed written form and subsequent codification make the standard variety more stable than purely spoken varieties, and provide a base for further development or ausbau. This variety becomes the norm for writing, is used in broadcasting and for official purposes, and is the form taught to non-native learners.
Through this process, the standard variety acquires prestige and a greater functional importance than local varieties. Those varieties are said to be dependent on, or heteronomous with respect to, the standard variety, because speakers read and write the standard, refer to it as an authority is such matters as specialist vocabulary, and any standardizing changes in their speech are towards that standard. In some cases, such as Standard English, this process may take place over an extended period without government intervention. In others it may be deliberately directed by official institutions, such as the Académie française or Real Academia Española, and can proceed much more quickly.
Language standardization is often linked to the formation, or attempted formation, of nation states, as language is seen as the vehicle of a shared culture. Different national standards derived from a dialect continuum may be regarded as different languages, even if they are mutually intelligible. The Scandinavian languages, Danish, Norwegian and Swedish, are often cited as examples.
In other cases governments or neighbouring populations may seek to deny a standard independent status. In response, developers of a standard may base it on more divergent varieties. Thus after Norway became independent at the start of the 20th century, the Bokmål standard based on the speech of Oslo was felt to be too similar to Danish by Ivar Aasen, who developed a rival Nynorsk standard based on western varieties. Similarly, when a standard was developed in the Yugoslav republic of Macedonia from local varieties within a continuum with Serbia to the north and Bulgaria to the east, it was deliberately based on varieties from the west of the republic that were most different from standard Bulgarian. Now known as Macedonian, it is the national standard of the independent Republic of Macedonia, but viewed by Bulgarians as a dialect of Bulgarian.
Arabic comprises many varieties (some of which are mutually unintelligible) which are considered a single language because the standardised register of Arabic, called Modern Standard Arabic, is generally intelligible to literate speakers. It is based on simplified Classical Arabic, the language of the Quran, which dates from the 7th century CE.
The Aramaic language has been diglossic for much of its history, with many different literary standards serving as the "high" liturgical languages, including Syriac language, Jewish Palestinian Aramaic, Jewish Babylonian Aramaic, Samaritan Aramaic language and Mandaic language, while the vernacular Neo-Aramaic languages serve as the vernacular language spoken by the common people like Northeastern Neo-Aramaic (Assyrian Neo-Aramaic, Chaldean Neo-Aramaic, Western Neo-Aramaic, Turoyo language, Lishana Deni, Lishanid Noshan and Lishán Didán).
Assyrian Neo-Aramaic, the most commonly spoken Aramaic variety today, has two standardized dialects: Standard Urmian, which is based in Iran, and the more popular Iraqi Koine, which is a koine dialect that features elements of the Urmian dialect and the Hakkari dialects such as Tyari, Barwari, Jilu and/or Nochiya, among others.
Cantonese (粵語）is a language spoken in the Chinese province of Guangdong. It is a de facto standard language used by the court, media, schools, and the government in Hong Kong and Macau. The standard accent of Cantonese spoken in Hong Kong and Macau is based on the accent of West Gate (西關) in modern-day western Guangzhou and is mutually intelligible with the Cantonese spoken in Guangzhou, although there exist minor differences in pronunciation and vocabulary due to its evasion of Mandarin influence and communist ideologies.
In Hong Kong Cantonese, the major difference from Guangzhou Cantonese is that the nasal sound /ŋ/ (ng) is either faded out or merged into /l/ or /m/ initials. There is also a set of loanwords and unique slangs developed in Hong Kong. Hong Kong people also tend to speak Cantonese mixed with certain English vocabulary.
Chinese consists of hundreds of local varieties, many of which are not mutually intelligible, usually classified into seven to ten major groups, including Mandarin, Wu, Yue, Hakka and Min. Before the 20th century, most Chinese spoke only their local variety. For two millennia, formal writing had been done in Literary Chinese (or Classical Chinese), a style modelled on the classics and far removed from any contemporary speech. As a practical measure, officials of the late imperial dynasties carried out the administration of the empire using a common language based on Mandarin varieties, known as Guānhuà (literally "speech of officials").
In the early 20th century, many Chinese intellectuals argued that the country needed a standardized language. By the 1920s, Literary Chinese had been replaced as the written standard by written vernacular Chinese, which was based on Mandarin dialects. In the 1930s, Standard Chinese was adopted, with its pronunciation based on the Beijing dialect, but with vocabulary also drawn from other Mandarin varieties and its syntax based on the written vernacular. It is the official spoken language of the People's Republic of China (where it is called Pǔtōnghuà "common speech") and of the Republic of China governing Taiwan (as Guóyǔ "national language"), and one of the official languages of Singapore (as Huáyǔ "Chinese language"). Standard Chinese now dominates public life, and is much more widely studied than any other variety of Chinese.
The Chinese language also enjoys official status in Hong Kong (together with English) and in Macau (together with Portuguese). Although the written standard is widely understood and used almost exclusively on formal and semi-formal occasions (e.g. government documents, books) while the spoken standard is often taught at school, Standard Chinese is not widely employed in these areas. In daily life, most of the population speak Cantonese, the prestige dialect of Yue, and often write it on casual occasions (e.g. text messages, advertisements). Even when they read out a passage in the written standard, they would read it with the Cantonese pronunciation of each character, not Mandarin.
Dutch is a monocentric language, with all speakers using the same standard form (authorized by the Dutch Language Union) based on a Dutch orthography employing the Latin alphabet when writing. A process of standardisation of Dutch started in the Middle Ages, especially under the influence of the Burgundian Ducal Court in Dijon (Brussels after 1477). Till then every region spoke a different Middle Dutch dialect. The dialects of the County of Flanders and the Duchy of Brabant were the most influential around this time. The process of standardisation became much stronger at the start of the 16th century, mainly based on the urban dialect of Antwerp. In 1585 Antwerp fell to the Spanish army: many from the Southern Netherlands fled to the Northern Netherlands (that declared itself independent from Spain), especially to the province of Holland, where they influenced the urban dialects. In 1637, a further important step was made towards a unified language,  when the Statenvertaling, the first major Bible translation into Dutch, was created that people from all over the new republic could understand. It used elements from various dialects but was predominantly based on the urban dialects of Holland of post 16th century. 
In the Southern Netherlands (now Belgium and Luxembourg) developments were different. Under Spanish, then Austrian, and then French rule standardisation of Dutch language came to a standstill. The state, law, and increasingly education used French, yet more than half the Belgian population were speaking a Dutch dialect. In the course of the nineteenth century the Flemish movement stood up for the rights of Dutch, mostly called Flemish. But in competing with the French language the variation in dialects was a serious disadvantage. Since standardisation is a lengthy process, Dutch-speaking Belgium associated itself with the standard language that had already developed in the Netherlands over the centuries. Therefore, the situation in Belgium is essentially no different from that in the Netherlands, although there are recognisable differences in pronunciation, comparable to the pronunciation differences between standard British and standard American English. In 1980 the Netherlands and Belgium concluded the Language Union Treaty. This treaty lays down the principle that the two countries must gear their language policy to each other, among other things, for a common system of spelling.
In British English the standard, known as Standard English (SE), is historically based on the language of the medieval English court of Chancery. The late seventeenth and eighteenth centuries saw the establishment of this standard as the norm of "polite" society, that is to say of the upper classes. The spoken standard has come to be seen as a mark of good education and social prestige. Although often associated with the RP accent, SE can be spoken with any accent.
Standard Estonian was developed on the basis of the Central dialect of the North Estonian dialect group, being most similar to the sub-dialects spoken a little southeast of the capital Tallinn. The standard was developed in the 19th century after a long regional and language strife between Northern Estonia and Southern Estonia and their corresponding dialect groups.
By today, the standard has practically replaced all Northern Estonian dialects, with only the West Estonian archipelago retaining its local island varieties, although their dialects are in strong decline as well (the exception being the Kihnu island sub-dialect). Some South Estonian dialects like Mulgi and Tartu have been more or less replaced by Standard Estonian as well, while Võro and Seto in the southeast corner of Estonia are still alive and commonly spoken.
The Standard Estonian language itself varies in its accents in the West Estonian archipelago, with distinctive main island accents, and in Southern Estonia.
Filipino is the standardized form of the Metro Manila dialect of Tagalog, and is an official language of the Philippines. Most regions have a different Philippine language as their first language, but all Filipinos learn Tagalog in school. Tagalog is thus used as a lingua franca, with national television employing it almost exclusively, and with national printed media are sometimes in Tagalog but more often in English.
The basic structure and words of standard Finnish (yleiskieli) are mostly based upon the dialects of Western Finland, because Mikael Agricola, who codified the written language in the sixteenth century, was from Turku, the regional centre of the time. Finnish was developed to integrate all of the nation’s dialects, and so yield a logical language for proper written communication. One aim was national unification, in accordance to the nationalistic principle; the second aim was linguistic regularity and consistency, even if contradicting general colloquial usage, e.g. in Standard Finnish, ruoka becomes ruoan, and the pronunciation is ruuan.
The Georgian language has a literary liturgical form, the Old Georgian language, while the vernacular spoken varieties are the Georgian dialects and other related Kartvelian languages like Svan language, Mingrelian language, and Laz language.
Standard German was developed over several centuries, during which time writers tried to write in a way intelligible to the greatest number of readers and speakers, thus, until about 1800, Standard German was mostly a written language. In that time, in northern Germany and in the Netherlands and Flanders Low German and Low Franconian dialects were spoken that were much different from Standard German. Later, the Northern pronunciation of written German became considered the universal standard; in Hanover, because of that adoption, the local dialect disappeared. The Netherlands and Flanders developed standard languages of their own towards the end of the 16th century.
The standard form of Modern Greek is based on the Southern dialects; these dialects are spoken mainly in the Peloponnese, the Ionian Islands, Attica, Crete and the Cyclades. However the Northerners call this dialect, and the standard form, 'Atheneika' which means 'the Athens dialect'. This form is also official in Cyprus, where people speak a South-Eastern dialect (dialects spoken in the Dodecanese and Cyprus), Cypriot Greek and a Greek variant spoken in Southern Albania called Himariote Greek.
Two standardised registers of the Hindustani language have legal status India: Standard Hindi (one of 23 co-official national languages) and Urdu (Pakistan ’s official tongue), resultantly, Hindustani often called “Hindi-Urdu". 
Standard Hungarian is based on the Hungarian dialect originally spoken in the territory what is today part of Northeastern Hungary, Carpathian Ruthenia (Ukraine), Kosice Region of Slovakia and Satu Mare and Bihor counties of Romania, as both Bible translator Gáspár Károli (1529-1591) and language reformer Ferenc Kazinczy (1759-1831) were born in this region. However standard Hungarian first spread in the 19th century in the that day predominantly German speaking Budapest, today it is spoken by the overwhelming majority of Hungarians, partially due to television programs.
An Caighdeán Oifigiúil ("The Official Standard"), often shortened to An Caighdeán, is official standard of the Irish language. It is taught in most schools in Ireland, though with strong influences from local dialects. It was first published by the translators in Dáil Éireann in the 1950s.  As of September 2013,  the first major revision of the Caighdeán Oifigiúil is available, both online  and in print.  Among the changes to be found in the revised version are, for example, various attempts to bring the recommendations of the Caighdeán closer to the spoken dialect of Gaeltacht speakers,  including allowing further use of the nominative case where the genitive would historically have been found. 
Standard Italian is derived from the Tuscan dialect, specifically from its Florentine variety — the Florentine influence upon early Italian literature established that dialect as base for the standard language of Italy. In particular, Italian became the language of culture for all the people of Italy, thanks to the prestige of the masterpieces of Dante Alighieri, Francesco Petrarca, Giovanni Boccaccio, Niccolò Machiavelli, and Francesco Guicciardini. It would later become the official language of all the Italian states, and after the Italian unification it became the national language of the Kingdom of Italy.  Modern Standard Italian's lexicon has been deeply influenced by almost all regional languages of Italy while its received pronunciation (known as Pronuncia Fiorentina Emendata, Amended Florentine Pronunciation) is based on the accent of Romanesco (Roman dialect); these are the reasons why Standard Italian differs significantly from the Tuscan dialect. 
Classical Latin was the literary standard dialect of Latin spoken by higher socioeconomic classes, as opposed to the Vulgar Latin which is the generic term of the colloquial sociolects of Latin spoken across the Roman Empire by uneducated and less-educated classes. The Latin brought by Roman soldiers to Gaul, Iberia, or Dacia was not identical to the Latin of Cicero, and differed from it in vocabulary, syntax, and grammar. Some literary works with low-register language from the Classical Latin period give a glimpse into the world of early Vulgar Latin. The works of Plautus and Terence, being comedies with many characters who were slaves, preserve some early basilectal Latin features, as does the recorded speech of the freedmen in the Cena Trimalchionis by Petronius Arbiter. At the third Council of Tours in 813, priests were ordered to preach in the vernacular language — either in the rustica lingua romanica (Vulgar Latin), or in the Germanic vernaculars — since the common people could no longer understand formal Latin. Catholic Church continued to use Latin at present, and the name of the form of Latin is named Ecclesiastical Latin which is regarded a modernized standard dialect of Latin based on simplified Classical Latin with some lexical variations, a simplified syntax in some cases, and, commonly, an Italianized pronunciation.
The Malay language exists in a Classical variety, and modern standard variety and several vernacular dialects. The modern standard variety is based on Johore-Riau dialect of Malay. Indonesian is one of the variants of the Malay language.
Standard Manchu was based on the language spoken by the Jianzhou Jurchens during Nurhaci's time, while other unwritten Manchu dialects such as that of Aigun and Sanjiazi were also spoken in addition to the related Xibe language.
Classical Mongolian language was the high register used for religious and official purposes while the various Mongolian dialects serve as the low reigster, like Khalkha Mongolian, Chakhar Mongolian, Khorchin Mongolian, Kharchin Mongolian, Baarin Mongolian, Ordos Mongolian, and the Buryat language. The Tibetan Buddhist canon was translated into Classical Mongolian. The Oirat Mongols who spoke the Oirat Mongol language and dialects like Kalmyk language or Torgut Oirat used a separate standard written with the Clear script.
The Mongolian language, based on Khalkha Mongolian, now serves as the high register in Mongolia itself while in Inner Mongolia a standard Mongolian based on Chakhar Mongolian serves as the high register for all Mongols in China. The Buryat language has been turned into a standard literary form itself in Russia.
In Norwegian there are two parallel standard languages: (i) Bokmål (partly derived from the local pronunciation of Danish, when Denmark ruled Norway), (ii) Nynorsk (comparatively derived from Norwegian dialects).
Portuguese has two official written standards, (i) Brazilian Portuguese (used chiefly in Brazil) and (ii) European Portuguese (used in Portugal and Angola, Cape Verde, East Timor, Guinea-Bissau, Macau, Mozambique, and São Tomé and Príncipe). The written standards slightly differ in spelling and vocabulary, and are legally regulated. Unlike the written language, however, there is no spoken-Portuguese official standard, but the European Portuguese reference pronunciation is the educated speech of Lisbon.
In Brazil, actors and journalists usually adopt an unofficial, but de facto, spoken standard Portuguese, originally derived from the middle-class dialect of Rio de Janeiro, but that now encompasses educated urban pronunciations from the different speech communities in the southeast. In that standard, ⟨s⟩ represents the phoneme /s/ when it appears at the end of a syllable (whereas in Rio de Janeiro this represents /ʃ/) the rhotic consonant spelled ⟨r⟩ is pronounced [h] in the same situation (whereas in São Paulo this is usually an alveolar flap or trill). European and African dialects have differing realizations of /ʁ/ than Brazilian dialects, with the former using [ʁ] and [r] and the latter using [x], [h], or [χ].  Between vowels, ⟨r⟩ represents /ɾ/ for most dialects.
Four standard variants of the pluricentric Serbo-Croatian are spoken in Bosnia and Herzegovina, Croatia, Montenegro and Serbia.  They all have the same dialect basis (Štokavian).    These variants do differ slightly, as is the case with other pluricentric languages.   The differences between the variants do not hinder mutual intelligibility and do not undermine the integrity of the system as a whole.    Compared to the differences between the variants of English, German, French, Spanish, or Portuguese, the distinctions between the variants of Serbo-Croatian are less significant.   Serbia, Croatia, Bosnia and Herzegovina, and Montenegro in their constitution have all named the language differently. 
In Somalia, Northern Somali (or North-Central Somali) forms the basis for Standard Somali, particularly the Mudug dialect of the northern Darod clan. Northern Central Somali has frequently been used by famous Somali poets as well as the political elite, and thus has the most prestige among other Somali dialects. Standardization of the language is regulated by the Regional Somali Language Academy.
In Spain, Standard Spanish is based partly upon the speech of educated speakers from Madrid, but mainly upon the literary language. In Argentina and Uruguay the Spanish standard is based on the local dialects of Buenos Aires and Montevideo. This is known as Rioplatense Spanish (“River Plate Spanish"), distinguishable, from other standard Spanish dialects, by the greater use of the voseo. Like Rioplatense Spanish, all Standard Spanish dialects in all Latin America, United States, and Canary Islands are related to Andalusian Spanish.
Classical Tibetan was the high register used universally by all Tibetans while the various mutually unintelligible Tibetic languages serve as the low register vernacular, like Central Tibetan language in Ü-Tsang (Tibet proper), Khams Tibetan in Kham, Amdo Tibetan in Amdo, Ladakhi language in Ladakh, and Dzongkha in Bhutan. Classical Tibetan was used for official and religious purposes, such as in Tibetan Buddhist religious texts like the Tibetan Buddhist canon and taught and learned in monasteries and schools in Tibetan Buddhist regions.
Now Standard Tibetan, based on the Lhasa dialect, serves as the high register in China. In Bhutan, the Tibetan Dzongkha language has been standarized and replaced Classical Tibetan for official purposes and education, in Ladakh, the standard official language learned are now the unrelated languages Hindi-Urdu and English, and in Baltistan, the Tibetan Balti language serves as the low register while the unrelated Urdu language is the official language.
Modern standard Turkish is based on the dialect of Istanbul. Dialectal variation persists, in spite of the levelling influence of the standard used in mass media and the Turkish education system since the 1930s.
Uzbek and Uyghur
The Turkic Chagatai language had served as the high-register literary standard for Central Asian Turkic peoples, while the vernacular low-register languages were the Uzbek language and Eastern Turki (Modern Uyghur). After the Soviet Union abolished Chagatai as the literary standard, the Uzbek language was standarized as a literary language, and the Taranchi dialect of Ili was chosen as the literary standard for Modern Uyghur. Other dialects like the Kashgar and Turpan dialects continue to be spoken.