The idea that Proto-Germanic had substantial influence from Pre-IE substrate languages has been around for a very long time and still pops up in discussions about the development of the language, with claims about upwards to a 1/3 of Germanic words being non-IE.
However, most of these assertions are based on outdated research that has been largely discredited, and this video will go through the central arguments of the Germanic substrate theory and show that major influence of Pre-IE languages on Pgmc is greatly exaggerated and unlikely.
