Do you believe Satoshi was a pseudonym used by more than one person that's why there's differences in written English ?
Opsec.
He was trying to throw people off his scent.
Satoshi was a pseudonym -- this person does not exist under this name. He used disposable emails. He paid for the domain with an anonymous registration agent. Presumably he only connected with tor.
He didn't want to be found, and he went to great lengths to ensure that.
So, 'z' versus 's' was a way to throw people off his scent.
The way to analyse this would be to graph is 's' versus 'z' over time. Did he use 'z' for the first half of his posts, or the last half? Are they consistently mixed at all times?
And no, I don't believe that Satoshi was a team of people. Single, clever individuals do great things all the time by finding combinations of old ideas into new.
Very few people in the world could keep a secret like this for so long if they were a team.
I agree with this, the stronger evidence that satoshi was not a group of people is that we have not found a single person that can say they were part of team satoshi, keeping a secret especially one that includes the creation of a form of money that could potentially change the world is simply impossible so this fact alone should point out that satoshi was a single person, also Occam’s Razor indicates this is the most likely possibility, and about the different spellings of the words, this could be something as simple as satoshi using several computers to connect to the forum and some had a British English dictionary while the others had an international one.