Constitution of The Republic of Lithuania (approved by the citizens of the Republic of Lithuania in the Referendum on 25 October 1992):
Article 14. Lithuanian shall be the State language.
Article 117. In the Republic of Lithuania, court trials shall be conducted in the State language. Persons who do not speak Lithuanian shall be guaranteed the right to participate in investigation and court proceedings through an interpreter.
Law on the State Language (1995)
Law on the Amendment of the Republic of Lithuania Law on the Status of the State Commission of the Lithuanian Language (2001)
State Language Policy Guidelines 2003–2008