title_body: Are there languages with five conjugations? If not, how would one construct one?
upvoted_answer: If you have two features (number/person), it seems tricky to have five options (or any other odd number for that matter). However, there is an easy way: simply collapse singular and plural for one of the persons. 
  
  There is actually a real example in English (and several other languages): the pluralis majestatis ("Royal We"). Simply discard the first person singular and use the first person plural instead.
  
  We are not sure what other languages use this, but we have definitely heard it in English and German. It would not be surprising to us if it occurred in other languages as well.
  
  Sounds a bit odd, but would be an easy option.