Good thing that the spanish translator had the idea of creating a short glossary at the end of the book.
He didn't create that, only translated. Sapkowski made that glossary. In Narrenturm it's not very big, but in Warrors of God and Lux Perpetua it is pretty extensive. And I don't mind seeing a Latin sentences in the book, because it helps to better feel the old times.
And seriously - what's the problem with those sentences? Almost all of them are translated at the end.