I
Iros
Guest
It was an accident in that they didn't have any specific reason we know of to make their decision, but they didn't just pick the name out of thin air - the translators knew that it could have been translated as either Aeris or Aerith. I suppose we don't know that they didn't just flip a coin when originally deciding which one to go with, but it's pretty plausible they picked the one that sounded best to them. It's what they did with other names, after all - we need an English equivalent to this name, these are the options that are reasonably close to the Japanese version, what sounds best?