We usually speak as who we are, per our personality.
This is something that's become more and more evident as I wrestle with the dilemmna of my SIL.
See, she's an abrupt, to the point, straight shooting person, and hence she speaks like that. It matches her personality.
Ex: Brenda: please do such and such, thanks.
Me for example, I would write, "Brenda, would you please do this for me? I would appreciate it, thanks."
Difference is in the abrupt and relaxed styles. If you tend to be laid back, you are writing/speaking in a relaxed manner. If you tend to be abrupt, you clip off your sentences and write/speak in the same manner. Programmers are a good example, mathematicians, another.
I would suspect that Ashton speaks in a thoughtful, complex manner, because he has a thoughtful complex personality. I would suspect that Box talks in a rushed, run together manner, that is somewhat haphazard, because he has a personality where he feels like he's rushing, or hurrying to present things, not necessarily an impatient one, but more like an eager one. He's eager to present his views.
I would have to truly examine others styles to have any idea whether my theory is correct, but so far in many, it's matched. Ross for example, he had a negative, sarcastic and abrasive manner many times in his posts, and he seemed to be a negative personality to boot.
So in a sense, our speaking/writing style reflects who and what we are.
That's my take on it, anyway.
Brenda