Lithuanian still retains many of the original features of the nominal morphology found in the common ancestors of the Indo-European languages like Sanskrit and Latin, and has therefore been the focus of much study in the area of Indo-European linguistics.
Again, nonsense from wikipedia.
Studies in the field of comparative linguistics have shown it to be the most conservative
Disputed and refuted studies.
They were from Poland & they had R1a haplogroup like Poles.
What else can you call them?
Certainly not Poles. No respected historian uses that term for the people who lived on the present RP territory in that period. Being a nation isn't about DNA, it is about shared cultural values and experiences. Not descent. You, for example, are not part of the nation.
Would you like it to be called Pre Polish Poland?
That would be more accurate.
Essentially for 11,000 + years Poles have been genetically the same R1a haplogroup people as they are today
There were no Poles 11000 years ago.