Libretos or Librettos: How To spell?
The word Libretos is misspelled against Librettos, which is plural of "Libretto"
Librettos has double "tt" is mispronounced as "t"Remember double 'TT' in between the strings libre & os which should not be misspelled with single 'T'
Wrong Spelling:  libre-t-os  Correct Spelling:  libre-tt-os 
Find more incorrect spellings of Librettos to spell right way.