Dumviral or Duumviral: How To spell?
The word Dumviral is misspelled against Duumviral, an adjective meaning "belonging to the duumviri the duumvirate."
Duumviral has double "uu" is mispronounced as "u"Remember double 'UU' in between the strings d & mviral which should not be misspelled with single 'U'
Wrong Spelling:  d-u-mviral  Correct Spelling:  d-uu-mviral 
Check more misspelled words of Duumviral to spell it correct.