The point that the researcher, Klaus Dona (who is an artist that calls himself a "spiritual researcher") is trying to make is that there was an ancient world-wide and connected civilization that all used this same "pre-sanskrit" language. He calls it "pre-sanskrit" because it is supposedly very similar to sanskrit, but even older.
The translator, Kurt Schildmann, President of the "German Linguistic Association", learned his languages traveling and in the German Military, where he learned Sanskrit. He has no linguistics degree. He is all about this same ancient civilization, though, along with Japanese Atlantis, giant bones, ancient aliens, crystal skulls and just about all of the rediculous fantasy history that is popular right now.