Eighteen languages in Turkey are currently listed as endangered, vulnerable, or have become extinct, according to UNESCO.

This is a result of decades of government policies that have not put other languages on an equal footing with Turkish, the first language of around 80 percent of the population.

The history of forced Turkification targeting non-Turkish languages and cultures goes back to the early years of the new Republic of Turkey in the 1920s and 1930s. Non-Turkish names of towns and villages across the country were Turkified and changed. In 1924, Turkish became the sole medium of education, except for a small number of non-Muslim schools.

In 1928, a student association in Istanbul launched a campaign to stop the public use of non-Turkish languages, and a 1934 law banned the adoption of non-Turkish surnames.

Kurdish is the mostly widely spoken mother tongue in Turkey after Turkish, but such is the number of Kurds -- some 15 percent of the population of around 80 million - that UNESCO does not see it as being in danger.

Other minority languages though are listed as endangered and the bans and pressure from the state and the public have had a deleterious effect.

Laz, the language of a people living in the Black Sea region of Turkey and parts of Georgia, is listed as a definitely endangered by UNESCO. According to the Istanbul-based Laz Cultural Association, there are an estimated 1.5 million Laz people in Turkey, around 70 percent of whom can understand the language, but only 40 percent can speak it.

"The two most important factors for preserving a language is family and state policies," said Gökhan Alptekin, the vice president of the association. "If parents speak their native language with their kids, the language will very likely survive throughout generations.

"But I learnt in my research that many Laz parents do not speak Laz with their children because they don't want them to have broken Turkish, and these parents themselves do not speak Laz with their own parents because it is considered a disgrace," he said.

"And the teachers who themselves are Laz put serious pressure on students to stop them speaking Laz. The children are terrified because they are told that they are secretly listened to by those outside when they speak Laz at home."

Alptekin said the government should help preserve languages in Turkey.

"TV channels, newspapers and other means of communication in Laz should be established with the support of the government. Laz people do not have any of these things in Turkey," he said.

A big reason for the elimination of non-Turkish languages was the 1913-1923 genocide that targeted Armenians, Assyrians and Greeks in Ottoman Turkey and the subsequent forced population exchange between Turkey and Greece.

Religion was the sole criterion in the swap of around 1.6 million Christians from Turkey and up to 400,000 Muslims from Greece so that numbers of Christians were sent to Greece, while Greek-speaking Muslims remained.

The Pontic Greek dialect, spoken in the Pontus region near the Black Sea, is "definitely endangered", UNESCO said, while the Cappadocian Greek dialect of central Turkey is extinct.

"After the Greek Christian expulsions from Pontus, the Muslim Pontians, excluded from the 1923 religion-based, forced population exchange treaty, spoke their Pontian dialect, but only at home and not in public. The Turkish governments required them to speak Turkish only," said George Mavropoulos, the founder of the Asia Minor and Pontos Hellenic Research Center in Chicago.

Professor Kyriakos Chatzikyriakidis, chair of the Pontic Studies Department at the Aristotle University of Thessaloniki, said if there were tens of thousands of Greeks-speaking Muslims in the Trabzon area at the time of the 1923 population exchange, there may be hundreds left, though it was impossible to be sure.

"Establishing new educational and research programmes in which the Pontic Greek dialect will be studied, opening courses at schools and universities related to the Pontic dialect and history and other similar activities could enhance the dialect's chances of survival," he said.

"When humanity tries to save a language, it actually tries to save a part of the world's cultural heritage. Every language is a monument of the world heritage, for every language embodies and discloses the thinking and culture of its speakers," Chatzikyriakidis said.

The two dialects of Armenian in Turkey - Homshetsma and Western Armenian - are also "definitely endangered", UNESCO said. The land which is now modern-day Turkey was once host to a large Armenian population, but up to 1.5 million Armenians were killed or expelled from what was then the Ottoman Empire from 1915 in a campaign that historians say was constituted genocide.

There are about 50,000 people speaking Western Armenian, mainly in Istanbul, but the number of the speakers of Homshetsma, the language of the Hamshen people who converted to Islam, is not known.

Anahit Khosroeva, a genocide scholar and lecturer at the Institute of History of the National Academy of Sciences in Armenia said that even after the republic was established after the collapse of the Ottoman Empire discrimination against Armenians had continued.

"Since the founding of Turkey in 1923, international laws have been ignored there. For instance, the United Nations condemns national discrimination. But Turkey continues to carry out a policy of assimilation adopted by its founders under the slogan 'one nation, one language, one flag and one country," she said.

"The 1915 physical genocide against Armenians and Assyrians has been transformed into a cultural genocide against these communities through the government's assimilationist policies," Khosroeva said.

The 1923 Treaty of Lausanne set Turkey's borders, but also defined the rights of non-Muslim minorities. But the Assyrians in Turkey were excluded from the treaty and so still do not officially have the right to education in their mother tongue. There are currently around 25,000 Assyrians in Turkey today but only 4,000 or 5,000 can speak the Assyrian language.

The UNESCO Interactive Atlas lists four Assyrian dialects in Turkey: Suret (definitely endangered), Turoyo (severely endangered), Hertevin (critically endangered) and Mlahso (extinct).

Many Assyrians have moved to Europe in recent decades as fighting between the state and Kurdish rebels raged in their homelands in Turkey's east and southeast.

Nicholas Al-Jeloo, an expert on Assyrian history, said the Turkish government could help preserve the language by providing incentives and, above all, security for Assyrians to return.

The reason why non-Turkish languages in Turkey are struggling to survive is that the state has tried to wipe out other, non-Turkish identities, said Zeynem Arslan, the editor of the book "Zazaki - Yesterday, Today and Tomorrow" about the Zazaki language and people, mainly in eastern Turkey.

"Turkish hegemony is imposed on them. The problem in Turkey is the monist, annihilationist mentality that bases its existence on exterminating others," Arslan said. Zazaki is an Indo-European language, related to Persian, but with strong influences from Kurdish. It is spoken by between 4 to 6 million people, but UNESCO lists it in its vulnerable category of languages.

"The Zazaki language has for long years been banned officially. And no support has been given by the state to develop this language," Arslan said.

"For a vulnerable or endangered language to live on, the political environment should be more democratic and pluralistic," he said. "Multilingualism and official recognition of cultural rights should be adopted as government policy."