Creating one voice

A thought that occurred to me recently and which I mentioned in conversation to a friend is the idea of one's own voice or differing voices.

I know that sometimes I have thought that my phone voice differs from my natural voice as in when I am talking to someone. Furthermore I can have an online voice, experienced in forums such as Facebook (it's getting like the Starbucks of the internet).

I don't like the differences in those voices. To me it's not real. Real for me, I think is creating one voice. That, I believe is genuine, it is sincere. That is what people can trust.

Of course in creative writing it goes without saying, so why am I? So why am I, that there are many voices in characters.............