Lithuanian underwent fewer changes than other European languages languages from the same root language that begat all the proto-Indo-European languages. So it shares a lot of similar words with Sanskrit which is extremely well preserved.

https://media.licdn.com/dms/image/v2/C4D22AQGncdnVV2H6Mg/fee...

Other languages like English mutated too much so it shares fewer similarities to Sanskrit.

It's a small language that has everything: a complicated case system, genders, a unique vocabulary, and even freaking tones.