Apparently Ladino was used as a trade language throughout the Mediterranean/Adriatic, and Wikipedia lists it as being "native" to Italy [1]. There also are regional Judeo-Italian dialects, including two from Corfu [2].

My internal map of Italy isn't very good, but given the 'size' of the populations that must speak or have spoken these dialects, I'd guess there was a dialect specific to Sicily.

[1] https://en.wikipedia.org/wiki/Judaeo-Spanish [2] https://en.wikipedia.org/wiki/Judeo-Italian_languages#Dialec...