Improvisatori or Improvvisatori: How To spell?
The word Improvisatori is misspelled against Improvvisatori, which is plural of "Improvvisatore"
Improvvisatori has double "vv" is mispronounced as "v"Remember double 'VV' in between the strings impro & isatori which should not be misspelled with single 'V'
Wrong Spelling:  impro-v-isatori  Correct Spelling:  impro-vv-isatori 
Find more incorrect spellings of Improvvisatori to spell right way.