Sufixing or Suffixing: How To spell?
The word Sufixing is misspelled against Suffixing, which is present continuous of "Suffix"
Suffixing has double "ff" is mispronounced as "f"Remember double 'FF' in between the strings Su & ixing which should not be misspelled with single 'F'
Wrong Spelling:  Su-f-ixing  Correct Spelling:  Su-ff-ixing 
Check more misspelled words of Suffixing to spell it correct.