"Ni haash yinilyé?"
Translation:What is your name?
yinílyé means your name but Ni meaning "you (sg.)" Might just designate the focus or subject.
Just like Spanish, "yo soy un hombre" is sort of the same as "soy un hombre." Navajo is the same way. However, the verb yi"ni"lyé has "ni" in it already and is kind of redundant if you say it at the beginning unless you want to emphasize.
*Niísh 'éí haanílyé? It is used to sound less forward. Going up to someone and asking "Haanílyé?" sounds very forward and can sound rude in certain situations. Yes, it may seem that "ni" is redundant (which it is) but in this case it helps to sound less direct and confrontation and more polite.