"My paternal grandmother has an uncle."
Translation:Shí nalí asdzaan adáʼí bee hólǫ́.
with/by him (or her)
Bee hólǫ́ means "it is/exists with her" = "she has".
Shí nalí asdzaan adáʼí bee hólǫ́ = my paternal grandmother, an uncle with/by her exists.
Judorange123 explains it a little here: https://forum.duolingo.com/comment/29193444
The problem is most Navajo postpositions don't have direct English equivalents.