Certainly....interesting.

sounds like a head shrinkers worst nightmare

Hmm? They are the same person... Speak in tandem... Yet they behave differently?

I find this a most puzzling concept to wrap my head around. I accept it as greatness, though. Through you, I learned of the Star of India. What a magnificent gem.

This is the sort of being I would find great pleasure in speaking with. Looking at the seams, it begs to question if they were constructed. For what purpose- I can hardly speculate. The unified speaking method is very nostalgic for me. A character from a work of fiction I have great fondness has something alike to it. From Baten Kaitos Origins, a character named Guillo is a construct made by two wizards and speaks with both masculine and feminine voice simultaneously. While I'm not attempting to compare May & Mei to them, the experience of hearing them speak makes it quite easy to perceive their speaking patterns. Saying the same thing though... Do they speak in a manner that brings double entendres, or is Mei simply saying what May says facetiously?

They are a manifestation of bipolar disorder. Basically from one extreme to the other, via emotions.

The text explains that they say the same thing but with different emotions ^^

Okay, a literal case of a split personality.

Before anyone says anything, I just saw the obvious pun and had to say something. It's just impossible to resist.