On Love (Commentary on Plato's Symposium)

Besides the fact that the Pisans and Lucchese pronounce a single S in exchange for a simple Zeta, and for the double, two, saying Sansara, spasto pasture, Bellessa and duressa hardness.

The third was that different languages are not obliged to one another in their own sounds and elements, even if they sometimes use one another's characters: the ear compelling us sensibly to obey that which we hear in our own pronunciation; and not that which only the imagination represents to us, made upon an observance of other languages, and especially diverse ones: to which, perhaps, one would have to yield due to their antiquity and nobility, if we could give one single sound to each Zeta, as they do, be it single or double: but not being able to, nor should one even if one could, so as not to impoverish ourselves of those riches that nature has given us, it is better to try to keep them as distinct as possible, until a better way is found.

The fourth was the example of the greater part of the Tuscans, and among others, having Aldo Manuzio say in his Latin, Greek, and Hebrew principles that the Zeta is a double letter: and nevertheless, in the manner of all the other consonants, have placed it