well, quite an interesting (and quick) response..

MF: Can you give me some insight into how you came up with this list of English hard words?

GB: Sure... In this case the literal meaning of the Italian words was beside the point -- what mattered was only that the words be obscure and sound mysterious or "magical." So I picked words that looked vaguely similar (pseudo-cognates, I called them to myself) from the 1913 Webster's Unabridged (which seemed a decent analogue for the Melzi). It's one of several passages in the book where I as the translator got to have a bit of fun. (With Eco's oversight and approval, of course.)
best,
Geoff