Terminology like 'person', 'self', 'personality' are very easy as long as there's only one per - well - body, to say it bluntly. But then there's more than one (whatever there is more than one thing of), and things get confusing.
Remember, this is still all language. (Following is my opinion/theory, not necessarily truth. Probably a bit philosophical/ranting. Will be a bit long.)
Words like those are old and ill-defined. They hold no value in themselves. They're just containers for some concept humans imagine.
All things physical are easy to define. It is easily possible to do that with, say, an apple. Just take something, and give it a word/name. Things that are not possible to touch (whether it's a personality, alter, ego-state, thought, whatever) are hard to define. Because it's not possible to say 'look, here, this thing in my hand is a thought/personality/whatever'. (Hope you get the idea).
A word only has the meaning people give to it. Just like money, when people stop believing it, it does not exist anymore.
We could just say, from now on, a person is a living human body with the abilities tribeofone posted. By that definition, alters are not a separate person, but indeed part of that person.
We could also say, a person is something that has feelings, an identity (f.e. name/gender/age/etc) and the abilities tribeofone posted. In that definition, alters *are* separate persons.
What I'm trying to say here, it all depends on what we think what those words mean, the words themselves don't contain any meaning. It's only humans (speaking a particular language) that attach a meaning to them.
So, what do we want a 'personality' to be, exactly? Anyone got a well-sounding definition?

lifelongthing wrote:I can breathe, answer you and use this brain in my head, so in the end, the fact that you can even
have that argument with me means you've lost

lol. And very true, indeed.