Interchangeable ch/sh and k/t characters

[Mauro]

 Beware that there are saint names with non-Italian characters, namely "ñ" ("San Raimondo di Peñafort.") and "á" ("San Josemaria Escrivá").  Removing those would be cheating...

I have to confess I changed Peñafort to Pegnafort (I can never remember the Alt code for ñ, now I have just copied the ñ from your quote), and Escrivá to Escrivà (I had no idea it was a different 'a'). Two characters won't change much, don't ask me to re-do everything again

If I read the first table correctly, it says that the distance d(L,I) from the List to the Italian texts is about the same as the distance d(C,I) from the latter to Caesar's book; but the distance d(L,C) is a bit bigger that both. 

I'm not sure if I understand what you mean. Be careful not to confuse Dante - Divina commedia Inferno (text #15), which is in Italian and clusters with Italian texts, and Dante - De vulgaris eloquentia (text #16) which is written by Dante but in Latin and, indeed, clusters with the De Bello Gallico, as shown by the green squares. You can also see how the colour in the first column (or row) of the tables changes from yellow-green to yellow-orange moving from Dante - Divina Commedia down to Dante - De vulgaris eloquentia.

Then yes: the distance from the list of saints to Italian is comparable to the distance between Italian and Latin. Something like this:

   

What one can say is that, after Italian, Latin is the language most similar to the list of saints.

(by the way, I noticed now that there is a text in the table which is duplicated, the two texts by Baricco are both the same text).

But that is my point. This List is "aberrant" because it is not a discursive/narrative text, like all the others.  It has a very different nature, purpose, and structure, that causes its word frequency distribution to be extremely different from that of those texts; and that in turn causes the bigram frequencies to be very different too.  And yet the language is definitely Italian, and even mostof the words (even most of the names) are specifically Italian.

Of course I agree with you that the statistics of a text depend on the text itself. However in the great majority of cases the statistics (well, of bigrams at least, let's stick to them) are influenced more by the language than by the content, and even in texts very divergent from the 'normal texts' (as the saints list) the influence of the language is still dominant. Ie.: I'd bet that a list of English saints will sit closer to Darwin, Joyce and Milton than to the rest, while a list of German saints will be near Tristan (Thomas Mann).