In English, there are the 5 Ws: who, what, when, where, and why. The Navajo word háí is the “who” word, and in the instance that the object is not a person, it also means “which.”
Earlier, we gave you the “what” word (http://navajowotd.com/post/28360574873/ha-at-ii) – or há’át’íí / ha’íí. Notice how similar they are to each other.
A few useful phrases:
Háidíígíí — Which one
Háí bi- — Whose (Díísh háí bichidí? Whose vehicle is this?)
Háídíshą’ or Háidísh — Which (Háidísh nínízin? Which do you want?)
Háíshą’ or Háísh— Who (Háíshą’ ánít’į́? Who are you?)
[The post for “what” also contains a lot of useful phrases – check it out!]