John Scalzi, a very gifted and experienced writer, has a great post on this very subject.
Not to mention, a wonderful illustration:
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This is what came to mind when I read your post.![]()

Although I'm training myself to use "all right", I was always taught (in Canada, in the 60s) that "alright" is correct. So despite the fact that it is said that "alright" is "still considered an unacceptable alternative", I'm thinking that "alright" was the original spelling.
I blame "already."