Dear Alexandros

In my opinion, most MCDM methods allow for combining quantitative values with linguistics. For the latter, you have only to convert those linguistics expressions in numerical using an appropriate scale, even one of your invention. I would recommend just using the 0 -10 scale or the Likert scale.

Of course, it could be that original numerical, like 0.02, 0.8, 5067, etc, must be combined with the numbers 8,3, 5, etc., from converted linguistics, but it is a problem than can be easily solved by normalization

Based on Researcher perspective and skill. All MCDM Or MCDA techniques having a scale (like SAATH SCALE) then researcher is only takes linguistic term based on their Application.