As in so many Mudcat discussion all of you are right most of the time. You just use words differently.

As BigPinkLady has said, English, like German (or even Icelandic), is classified as a Germanic language, that is both have a common precursor. The inclusion of new words from completely different languages does not change this classification for it is based on different criteria.

A romanic language could integrate the very same word from, for instance, Hindi, but treat it differently according to its basic rules.

The similarity of words or the percentages of words taken from other languages surely determines the ease with which we can read in a language we don't know (though I tend to believe that my ability to read in Italian and Spanish without ever having learned them comes from my knowledge of French, and not from a similarity to German). But it is irrelevant with regard to the classification of languages.

I don't know of an example and maybe there isn't one, but two languages could share 90% of their vocabulary and still be classified differently.

Wolfgang