Paleo-European languages

"The study of the lexicon of the Northern European languages, especially Germanic and Baltic, reveals that a large number of terms relevant to the ecology of the habitat of the early populations of the area and to their socioeconomic activities have no plausible Indo-European etymology. (…) it is possible to ascribe to the pre-Indo-European substrate in the Baltic area a number of names of plants, animals, objects and activities characteristic of the Neolithic cultures."