Mutual intelligibility in the context of Common Slavic

Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign languages are full-fledged natural languages with their own grammar and lexicon. Sign languages are not universal and are usually not mutually intelligible, although there are similarities among different sign languages.

Wherever communities of people with hearing challenges or people who experience deafness exist, sign languages have developed as useful means of communication and form the core of local deaf cultures. Although signing is used primarily by the deaf and hard of hearing, it is also used by hearing individuals, such as those with deaf family members including children of deaf adults.

Chinese (spoken: simplified Chinese: 汉语; traditional Chinese: 漢語; pinyin: Hànyǔ, written: 中文; Zhōngwén) is an umbrella term for Sinitic languages in the Sino-Tibetan language family, widely recognized as a group of language varieties, spoken natively by the ethnic Han Chinese majority and many minority ethnic groups in China, as well as by various communities of the Chinese diaspora. Approximately 1.39 billion people, or 17% of the global population, speak one of the Chinese languages as their first language.

The Chinese languages form the Sinitic branch of the Sino-Tibetan language family. The Chinese government considers the spoken varieties of the Chinese languages dialects of a single language. However, their lack of mutual intelligibility means they are considered to be separate languages in a family by linguists. Investigation of the historical relationships among the varieties of Chinese is ongoing. Currently, most classifications posit 7 to 13 main regional groups based on phonetic developments from Middle Chinese, of which the most spoken by far is Mandarin with 66%, or around 800 million speakers, followed by Min (75 million, e.g., Southern Min), Wu (74 million, e.g., Shanghainese), and Yue (68 million, e.g., Cantonese). These branches are unintelligible to each other, and many of their subgroups are unintelligible with the other varieties within the same branch (e.g., Southern Min). There are, however, transitional areas where varieties from different branches share enough features for some limited intelligibility, including New Xiang with Southwestern Mandarin, Xuanzhou Wu Chinese with Lower Yangtze Mandarin, Jin with Central Plains Mandarin and certain divergent dialects of Hakka with Gan. All varieties of Chinese are tonal at least to some degree, and are largely analytic.

Urdu (اُرْدُو) is an Indo-Aryan language spoken primarily in South Asia. It is the national language and lingua franca of Pakistan. It is also an official Eighth Schedule language in India, the status and cultural heritage of which are recognised by the Constitution of India. It also has an official status in several Indian states.

Urdu and Hindi share a common, predominantly Sanskrit- and Prakrit-derived, vocabulary base, phonology, syntax, and grammar, making them mutually intelligible during colloquial communication. The common base of the two languages is sometimes referred to as the Hindi–Urdu or Hindustani language, and Urdu has been described as a Persianised standard register of the Hindustani language. While formal Urdu draws literary, political, and technical vocabulary from Persian, formal Hindi draws these aspects from Sanskrit; consequently, the two languages' mutual intelligibility effectively decreases as the factor of formality increases.

The Iberian Romance, Ibero-Romance or sometimes Iberian languages are a group of Romance languages that developed on the Iberian Peninsula, an area consisting primarily of Spain, Portugal, Gibraltar, Andorra and French Catalonia. They are today more commonly separated into West Iberian, East Iberian (Catalan/Valencian) and Southern Iberian (Andalusi Romance, also known as Mozarabic/Haketia) language groups. East Iberian's classification is a subject of ongoing scholarly debate, as some argue that the Occitano-Romance languages, composed of Occitan along with Catalan/Valencian, are better classified as Gallo-Romance languages.

Evolved from the Vulgar Latin of Iberia, the most widely spoken Iberian Romance languages are Spanish and Portuguese, followed by Catalan-Valencian-Balear and Galician. These languages also have their own regional and local varieties. Based on mutual intelligibility, Dalby counts seven "outer" languages, or language groups: Galician-Portuguese, Spanish, Asturleonese, "Wider"-Aragonese, "Wider"-Catalan, Provençal+Lengadocian, and "Wider"-Gascon.

Griko (endonym: Griko/Γκρίκο), sometimes spelled Grico, is one of the two dialects of Italiot Greek (the other being Calabrian Greek or Grecanico), spoken by Griko people in Salento, province of Lecce, Italy. Some Greek linguists consider it to be a Modern Greek dialect and often call it Katoitaliótika (Greek: Κατωιταλιώτικα, lit. 'Southern Italian') or Grekanika (Γραικάνικα). Griko and Standard Modern Greek are partially mutually intelligible.

Macedonian (/ˌmæsɪˈdoʊniən/ MASS-ih-DOH-nee-ən; македонски јазик, translit. makedonski jazik, pronounced [maˈkɛdɔnski ˈjazik] ) is an Eastern South Slavic language. It is part of the Indo-European language family, and is one of the Slavic languages, which are part of a larger Balto-Slavic branch. Spoken as a first language by around 1.7 million people, it serves as the official language of North Macedonia. Most speakers can be found in the country and its diaspora, with a smaller number of speakers throughout the transnational region of Macedonia. Macedonian is also a recognized minority language in parts of Albania, Bosnia and Herzegovina, Romania, and Serbia and it is spoken by expatriate communities predominantly in Australia, Canada, and the United States.

Macedonian developed out of the western dialects of the Eastern South Slavic dialect continuum, whose earliest recorded form is Old Church Slavonic. During much of its history, this dialect continuum was called "Bulgarian", although in the late 19th century, its western dialects came to be known separately as "Macedonian". Standard Macedonian was codified in 1945 and has developed modern literature since. As it is part of a dialect continuum with other South Slavic languages, Macedonian has a high degree of mutual intelligibility with Bulgarian and varieties of Serbo-Croatian.

Proto-Slavic (abbreviated PSl., PS.; also called Common Slavic or Common Slavonic) is the unattested, reconstructed proto-language of all Slavic languages. It represents Slavic speech approximately from the 2nd millennium BC through the 6th century AD. As with most other proto-languages, no attested writings have been found; scholars have reconstructed the language by applying the comparative method to all the attested Slavic languages and by taking into account other Indo-European languages.

Rapid development of Slavic speech occurred during the Proto-Slavic period, coinciding with the massive expansion of the Slavic-speaking area. Dialectal differentiation occurred early on during this period, but overall linguistic unity and mutual intelligibility continued for several centuries, into the 10th century or later. During this period, many sound changes diffused across the entire area, often uniformly. This makes it inconvenient to maintain the traditional definition of a proto-language as the latest reconstructable common ancestor of a language group, with no dialectal differentiation. (This would necessitate treating all pan-Slavic changes after the 6th century or so as part of the separate histories of the various daughter languages.) Instead, Slavicists typically handle the entire period of dialectally differentiated linguistic unity as Common Slavic.

Persian, also known by its endonym Farsi or Parsi, is a Western Iranian language belonging to the Iranian branch of the Indo-Iranian subdivision of the Indo-European languages. Persian is a pluricentric language predominantly spoken and used officially within Iran, Afghanistan, and Tajikistan in three mutually intelligible standard varieties, respectively Iranian Persian (officially known as Persian), Dari Persian (officially known as Dari since 1964), and Tajiki Persian (officially known as Tajik since 1999). It is also spoken natively in the Tajik variety by a significant population within Uzbekistan, as well as within other regions with a Persianate history in the cultural sphere of Greater Iran. It is written officially within Iran and Afghanistan in the Persian alphabet, a derivative of the Arabic script, and within Tajikistan in the Tajik alphabet, a derivative of the Cyrillic script.

Modern Persian is a continuation of Middle Persian, an official language of the Sasanian Empire (224–651 CE), itself a continuation of Old Persian, which was used in the Achaemenid Empire (550–330 BCE). It originated in the region of Fars (Persia) in southwestern Iran. Its grammar is similar to that of many European languages.

Kurdish (Kurdî, کوردی, pronounced [kʊrdiː] ) is a Northwestern Iranian language or group of languages spoken by Kurds in the region of Kurdistan, namely in southeast Turkey, northern Iraq, northwest Iran, and northern Syria. It is also spoken in northeast Iran, as well as in certain areas of Armenia and Azerbaijan.

Kurdish varieties constitute a dialect continuum, with some mutually unintelligible varieties, and collectively have 26 million native speakers. The main varieties of Kurdish are Kurmanji, Sorani, and Southern Kurdish (Xwarîn). The majority of the Kurds speak Kurmanji, and most Kurdish texts are written in Kurmanji and Sorani. Kurmanji is written in the Hawar alphabet, a derivation of the Latin script, and Sorani is written in the Sorani alphabet, a derivation of the Arabic script.

Armenians (Armenian: հայեր, romanized: hayer, [hɑˈjɛɾ]) are an ethnic group indigenous to the Armenian highlands of West Asia. Armenians constitute the main demographic group in Armenia and constituted the main population of the breakaway Republic of Artsakh until their subsequent flight due to the 2023 Azerbaijani offensive. There is a large diaspora of around five million people of Armenian ancestry living outside the Republic of Armenia. The largest Armenian populations exist in Russia, the United States, France, Georgia, Iran, Germany, Ukraine, Lebanon, Brazil, Argentina, Syria, and Turkey. The present-day Armenian diaspora was formed mainly as a result of the Armenian genocide with the exceptions of Iran, former Soviet states, and parts of the Levant.

Armenian is an Indo-European language. It has two mutually intelligible spoken and written forms: Eastern Armenian, today spoken mainly in Armenia, Artsakh, Iran, and the former Soviet republics; and Western Armenian, used in the historical Western Armenia and, after the Armenian genocide, primarily in the Armenian diasporan communities. The unique Armenian alphabet was invented in 405 AD by Mesrop Mashtots.

There are hundreds of local Chinese language varieties forming a branch of the Sino-Tibetan language family, many of which are not mutually intelligible. Variation is particularly strong in the more mountainous southeast part of mainland China. The varieties are typically classified into several groups: Mandarin, Wu, Min, Xiang, Gan, Jin, Hakka and Yue, though some varieties remain unclassified. These groups are neither clades nor individual languages defined by mutual intelligibility, but reflect common phonological developments from Middle Chinese.

Chinese varieties have the greatest differences in their phonology, and to a lesser extent in vocabulary and syntax. Southern varieties tend to have fewer initial consonants than northern and central varieties, but more often preserve the Middle Chinese final consonants. All have phonemic tones, with northern varieties tending to have fewer distinctions than southern ones. Many have tone sandhi, with the most complex patterns in the coastal area from Zhejiang to eastern Guangdong.

Malay (UK: /məˈleɪ/ mə-LAY, US: /ˈmeɪleɪ/ MAY-lay; endonym: Bahasa Melayu, Jawi script: بهاس ملايو) is an Austronesian language spoken primarily by Malays in several islands of Maritime Southeast Asia and the Malay Peninsula on mainland Asia. The language is an official language of Brunei, Malaysia, and Singapore. Indonesian, a standardized variety of Malay, is the official language of Indonesia and one of the working languages of Timor-Leste. Malay is also spoken as a regional language of ethnic Malays in Indonesia, southeast Philippines and the southern part of Thailand. Altogether, it is spoken by 60 million people across Maritime Southeast Asia.

The language is pluricentric and a macrolanguage, i.e., a group of mutually intelligible speech varieties, or dialect continuum, that have no traditional name in common, and which may be considered distinct languages by their speakers. Several varieties of it are standardized as the national language (bahasa kebangsaan or bahasa nasional) of several nation states with various official names: in Malaysia, it is designated as either Bahasa Melayu ("Malay language") or in some instances, Bahasa Malaysia ("Malaysian language"); in Singapore and Brunei, it is called Bahasa Melayu ("Malay language") where it in the latter country refers to a formal standard variety set apart from its own vernacular dialect; in Indonesia, an autonomous normative variety called Bahasa Indonesia ("Indonesian language") is designated the bahasa persatuan/pemersatu ("unifying language" or lingua franca) whereas the term "Malay" (bahasa Melayu) refers to vernacular varieties of Malay indigenous to areas of Central to Southern Sumatra and West Kalimantan as the ethnic languages of Malay in Indonesia.

Ukrainian (українська мова, ukrainska mova, IPA: [ʊkrɐˈjinʲsʲkɐ ˈmɔwɐ]) is an East Slavic language, spoken primarily in Ukraine. It is the first (native) language of a large majority of Ukrainians.

Written Ukrainian uses the Ukrainian alphabet, a variant of the Cyrillic script. The standard language is studied by the National Academy of Sciences of Ukraine and Potebnia Institute of Linguistics. Comparisons are often made between Ukrainian and Russian, another East Slavic language, yet there is more mutual intelligibility with Belarusian, and a closer lexical distance to West Slavic Polish and South Slavic Bulgarian.

Varieties of Arabic (or dialects or vernaculars) are the linguistic systems that Arabic speakers speak natively. Arabic is a Semitic language within the Afroasiatic family that originated in the Arabian Peninsula. There are considerable variations from region to region, with degrees of mutual intelligibility that are often related to geographical distance and some that are mutually unintelligible. Many aspects of the variability attested to in these modern variants can be found in the ancient Arabic dialects in the peninsula. Likewise, many of the features that characterize (or distinguish) the various modern variants can be attributed to the original settler dialects as well as local native languages and dialects. Some organizations, such as SIL International, consider these approximately 30 different varieties to be separate languages, while others, such as the Library of Congress, consider them all to be dialects of Arabic.

In terms of sociolinguistics, a major distinction exists between the formal standardized language, found mostly in writing or in prepared speech, and the widely diverging vernaculars, used for everyday speaking situations. The latter vary from country to country, from speaker to speaker (according to personal preferences, education and culture), and depending on the topic and situation. In other words, Arabic in its natural environment usually occurs in a situation of diglossia, which means that its native speakers often learn and use two linguistic forms substantially different from each other, the Modern Standard Arabic (MSA) as the official language and a local colloquial variety (called العامية, al-ʿāmmiyya in many Arab countries, meaning "slang" or "colloquial"; or called الدارجة, ad-dārija, meaning "common or everyday language" in the Maghreb), in different aspects of their lives.

Maltese (Maltese: Malti, also L-Ilsien Malti or Lingwa Maltija) is a Central Semitic language derived from late medieval Sicilian Arabic with Romance superstrata. It is the only Semitic language written in the Latin script. It is spoken by the Maltese people and is a national language of Malta, and is the only official Semitic and Afroasiatic language of the European Union. According to John L. Hayes, it descended from a North African dialect of Colloquial Arabic which was introduced to Malta when the Aghlabids captured it in 869/870 CE. It is also said to have descended from Siculo-Arabic, which developed as a Maghrebi Arabic dialect in the Emirate of Sicily between 831 and 1091. As a result of the Norman invasion of Malta and the subsequent re-Christianisation of the islands, Maltese evolved independently of Classical Arabic in a gradual process of Latinisation. It is therefore exceptional as a variety of historical Arabic that has no diglossic relationship with Classical or Modern Standard Arabic. Maltese is thus classified separately from the 30 varieties constituting the modern Arabic macrolanguage. Maltese is also distinguished from Arabic and other Semitic languages since its morphology has been deeply influenced by Romance languages, namely Italian and Sicilian.

The original Arabic base comprises around one-third of the Maltese vocabulary, especially words that denote basic ideas and the function words, but about half of the vocabulary is derived from standard Italian and Sicilian; and English words make up between 6% and 20% of the vocabulary. A 2016 study shows that, in terms of basic everyday language, speakers of Maltese are able to understand less than a third of what is said to them in Tunisian Arabic and Libyan Arabic, which are Maghrebi Arabic dialects related to Siculo-Arabic, whereas speakers of Tunisian Arabic and Libyan Arabic are able to understand about 40% of what is said to them in Maltese. This reported level of asymmetric intelligibility is considerably lower than the mutual intelligibility found between mainstream varieties of Arabic.

Dutch (endonym: Nederlands [ˈneːdərlɑnts] , Nederlandse taal) is a West Germanic language of the Indo-European language family, spoken by about 25 million people as a first language and 5 million as a second language and is the third most spoken Germanic language. In Europe, Dutch is the native language of most of the population of the Netherlands and Flanders (which includes 60% of the population of Belgium). Dutch was one of the official languages of South Africa until 1925, when it was replaced by Afrikaans, a separate but partially mutually intelligible daughter language of Dutch. Afrikaans, depending on the definition used, may be considered a sister language, spoken, to some degree, by at least 16 million people, mainly in South Africa and Namibia, and evolving from Cape Dutch dialects.

In South America, Dutch is the native language of the majority of the population of Suriname, and spoken as a second or third language in the multilingual Caribbean island countries of Aruba, Curaçao and Sint Maarten. All these countries have recognised Dutch as one of their official languages, and are involved in one way or another in the Dutch Language Union. The Dutch Caribbean municipalities (St. Eustatius, Saba and Bonaire) have Dutch as one of the official languages. In Asia, Dutch was used in the Dutch East Indies (now mostly Indonesia) by a limited educated elite of around 2% of the total population, including over 1 million indigenous Indonesians, until it was banned in 1957, but the ban was lifted afterwards. About a fifth of the Indonesian language can be traced to Dutch, including many loan words. Indonesia's Civil Code has not been officially translated, and the original Dutch language version dating from colonial times remains the authoritative version. Up to half a million native speakers reside in the United States, Canada and Australia combined, and historical linguistic minorities on the verge of extinction remain in parts of France and Germany.

Icelandic (/aɪsˈlændɪk/ eyess-LAN-dik; endonym: íslenska, pronounced [ˈi(ː)stlɛnska] , íslensk tunga [ˈi(ː)stlɛnsk ˈtʰuŋka]) is a North Germanic language from the Indo-European language family spoken by about roughly 390,000 people, the vast majority of whom live in Iceland, where it is the national language. Since it is a West Scandinavian language, it is most closely related to Faroese, western Norwegian dialects, and the extinct language Norn. It is not mutually intelligible with the continental Scandinavian languages (Danish, Norwegian, and Swedish) and is more distinct from the most widely spoken Germanic languages, English and German. The written forms of Icelandic and Faroese are very similar, but their spoken forms are not mutually intelligible.

The language is more conservative than most other Germanic languages. While most of them have greatly reduced levels of inflection (particularly noun declension), Icelandic retains a four-case synthetic grammar (comparable to German, though considerably more conservative and synthetic) and is distinguished by a wide assortment of irregular declensions. Icelandic vocabulary is also deeply conservative, with the country's language regulator maintaining an active policy of coining terms based on older Icelandic words rather than directly taking in loanwords from other languages.

Old French (franceis, françois, romanz; French: ancien français [ɑ̃sjɛ̃ fʁɑ̃sɛ]) was the language spoken in most of the northern half of France approximately between the late 8th and mid-14th centuries. Rather than a unified language, Old French was a group of Romance dialects, mutually intelligible yet diverse. These dialects came to be collectively known as the langues d'oïl, contrasting with the langues d'oc, the emerging Occitano-Romance languages of Occitania, now Southern France.

The mid-14th century witnessed the emergence of Middle French, the language of the French Renaissance in the Île-de-France region; this dialect was a predecessor to Modern French. Other dialects of Old French evolved themselves into modern forms (Poitevin-Saintongeais, Gallo, Norman, Picard, Walloon, etc.), each with its linguistic features and history.

Kyrgyz is a Turkic language of the Kipchak branch spoken in Central Asia. Kyrgyz is the official language of Kyrgyzstan and a significant minority language in the Kizilsu Kyrgyz Autonomous Prefecture in Xinjiang, China and in the Gorno-Badakhshan Autonomous Region of Tajikistan. There is a very high level of mutual intelligibility between Kyrgyz, Kazakh, and Altay. A dialect of Kyrgyz known as Pamiri Kyrgyz is spoken in north-eastern Afghanistan and northern Pakistan. Kyrgyz is also spoken by many ethnic Kyrgyz through the former Soviet Union, Afghanistan, Turkey, parts of northern Pakistan, and Russia.

Kyrgyz was originally written in Göktürk script, gradually replaced by the Perso-Arabic alphabet (in use until 1928 in the USSR, still in use in China). Between 1928 and 1940, a Latin-script alphabet, the Uniform Turkic Alphabet, was used. In 1940, Soviet authorities replaced the Latin script with the Cyrillic alphabet for all Turkic languages on its territory. When Kyrgyzstan became independent following the Soviet Union's collapse in 1991, a plan to adopt the Latin alphabet became popular. Although the plan has not been implemented, it remains in occasional discussion.