Help me with content in Italian (Blasco Ferrer- Sardinian language)

I hope you can help me. I have to do my term paper about the Sardinian language. Unfortunately I have problems with a certain text in Italian… No matter how many times I read it or i summarize it in my own words, I just don´t get the point.
I would be glat if you could tell my in short and very easy words the main idea of the text. Especially the opinion of Gröber and Wartburg. My mother tongue is German.
Thanks in advance!