It's in it's most basic form an endeerment. We put 'y' on things to make them sound cuter, like with a lot of nicknames. And Ninty is a nickname.

Or William = Bill

Microsoft - Mickey?

I had a perpetually drunk uncle who referred to them as Ingo at one point. It stuck as a name for a little while among my cousins and myself, but never caught on globally.

Richard = Rick or Dick or Richy or Ricky or Dicky

William = Will or Bill or Willy or Billy

I feel really bad for Microsofty.
Very unfortunate nickname.

By who?! o_o

Its like transgender/tranny.

Ninten, from Mother / Earthbound Beginnings.

If we called Nintendo Ninten people could think Nintendo cares about the IP.
We cannot have that kind of confusion.

Haha, I figured you meant Ninten from Mother, since other people why I was talking about that one xD

Surely they care enough to give us Mother 3... ; w ;