You may call it a nickname, I woud call it another, may be wrong, pronounciation
In Hebrew the sister of Moses and Aharon is MiR'JaM (from the root "mar" - bitter, or ram) with the accent on "a".
The Cristian world knows other Mirjam under the nickname Mariya (the virgine, mother of Jesus)
In Russian the female names preferred to be finished on vowel and it turns to be Merjama, Mirjama.
In Israel there is popular name Miri, Mira. These are nicknames.
May be we should discuss first the word's "nickname" meaning.
ps. What is Ann? n-n for the Hebrew Hana? Translation? or different pronounciation?
Josef ASH, Israel