[4][5] Originally, East Baltic was presumably native to the north of Eastern Europe, which included modern Latvia, Lithuania, northern parts of current European Russia and Belarus.

In addition, both groups had their own burial customs: unlike their Western counterparts, it is believed that East Balts would burn the remains of the dead and scatter the ashes on the ground or in nearby rivers and lakes.

[10] However, from the analysis of hydronyms and retained loanwords, it is known that Selonian and Old Curonian languages possessed the retention of nasal vowels *an, *en, *in, *un.

It is noted that Selonian, Semigallian and Old Latgalian palatalised soft velars *k, *g into *c, *dz while also depalatalising the sounds *š, *ž into *s, *z respectively.

This is observed in hydronyms and oeconyms (e.g. Zirnajai, Zalvas, Zarasai) as well as loanwords preserved in Lithuanian and Latvian dialects.

[12] East Baltic would in many cases turn the diphthong *ei into a monophthong, pronounced like the contemporary Latvian jē and Lithuanian ė.

Unlike their Western counterparts, East Baltic languages usually tend to keep their short vowels *o and *a separately (e.g. Lat.