Lithuanian is the oldest present Indo-European language and it is related to Sanskrit, Latin and Ancient Greek. It is the state language of Lithuania and an official language of the European Union. The language has about 3.2 million speakers in Lithuania and is also used by 4 million people across the whole world. There is large number of the Lithuanian community in Argentina, Australia, Brazil, Canada, Great Britain, Ireland, Germany, Latvia, Russia, Poland, Spain, USA, UK and Uruguay.

It is very important to the field of Indo-European language studies which carries out research on the origin, development, similarities and differences of Indo-European languages. Scientists of various countries in this field use Lithuanian as their main language of communication at their conferences and business. Lithuania is located in Northern Europe and Vilnius is its capital city.

Among Indo-European languages, Lithuanian is extraordinarily conservative, retaining many archaic features otherwise found only in ancient languages such as Sanskrit or Ancient Greek. For this reason, it is one of the most important sources in the reconstruction of the Proto-Indo-European language despite its late attestation (with the earliest texts dating only to c. 1500 AD).

The phonology and especially the nominal morphology of Lithuanian is almost certainly the most conservative of any living Indo-European language, although its verbal morphology is less conservative and may be exceeded by the conservatism of Modern Greek verbs, which maintain a number of archaic features lacking in Lithuanian, such as the synthetic aorist and mediopassive forms.