Sienese or Siennese: How To spell?
The word Sienese is misspelled against Siennese, an adjective meaning "pertaining to Sienna, a city Italy."
Siennese has double "nn" is mispronounced as "n"Remember double 'NN' in between the strings sie & ese which should not be misspelled with single 'N'
Wrong Spelling:  sie-n-ese  Correct Spelling:  sie-nn-ese 
Find more wrongly spelled words of Siennese to spell it well.