The correct spelling of the surname "Sisneros" is a matter of some debate. Some spell it with one "s" rather than two. The "s" sound in either case is pronounced with a "z" sound, as in "zis-ner-os". The first "s" is followed by a short "i" sound, and the "o" is pronounced with a long "o" sound. The final "os" is pronounced with a long "oh" sound, as in "Sis-ner-ohs". Regardless of spelling, the pronunciation remains the same.