Article 3 of the Constitution of Turkey defines Turkish as the only official language of Turkey.
Minority language rights
Article 42 of the Constitution explicitly prohibits educational institutions to teach any language other than Turkish as a mother tongue to Turkish citizens.
No language other than Turkish shall be taught as a mother tongue to Turkish citizens at any institutions of training or education. Foreign languages to be taught in institutions of training and education and the rules to be followed by schools conducting training and education in a foreign language shall be determined by law. The provisions of international treaties are reserved.
Due to Article 42 and its longtime restrictive interpretation, ethnic minorities have been facing severe restrictions in the use of their mother languages.
Concerning the incompatibility of this provision with the International Bill of Human Rights, Turkey signed the International Covenants on Civil and Political Rights and on Economic, Social and Cultural Rights only with reservations constraining minority rights and the right to education. Furthermore, Turkey hasn't signed either of the Council of Europe's Framework Convention for the Protection of National Minorities, the European Charter for Regional or Minority Languages, or the anti-discrimination Protocol 12 to the European Convention on Human Rights.
This particular constitutional provision has been contested both internationally and within Turkey. The provision has been criticized by minority groups, notably the Kurdish community. In October 2004, the Turkish State's Human Rights Advisory Board called for a constitutional review in order to bring Turkey's policy on minorities in line with international standards, but was effectively muted. It was also criticized by EU member states, the OSCE, and international human rights organizations, including Human Rights Watch who observe that "the Turkish government accepts the language rights of the Jewish, Greek and Armenian minorities as being guaranteed by the 1923 Treaty of Lausanne. But the government claims that these are Turkey's only minorities, and that any talk of minority rights beyond this is just separatism".
Supplementary language education
In 2012, the Ministry of Education included Kurdish (based on both Kurmanji and Zazaki dialects) to the academic programme of the basic schools as optional classes from the fifth year on.
Later, the Ministry of Education also included Abkhaz, Adyghe, Standard Georgian, and Laz languages in 2013, and Albanian as well as Bosnian languages in February 2017.
In 2015, the Turkey’s Ministry of Education announced that as of the 2016-17 academic year, Arabic courses (as a second language) will be offered to students in elementary school starting in second grade. The Arabic courses will be offered as an elective language course like German, French and English. According to a prepared curriculum, second and third graders will start learning Arabic by listening-comprehension and speaking, while introduction to writing will join these skills in fourth grade and after fifth grade students will start learning the language in all its four basic skills.