Typography and punctuation
English is a language complicated by style. While, sure, punctuation is influenced by grammar, sometimes usage is very much a matter of visual style. Some publications put things in quotation marks that would otherwise be italicised simply because their house font has killer quotation marks. Some publishers shy away from the use of semi-colons because they almost always mean complicated sentence structure. English linguists sometimes simply disagree about the value of a comma in a particular situation.
Geography can also play a role. There are some extraordinarily common uses of punctuation in Britain that don't get so much play in America.
That's why the Tardis Manual needs to have a chapter explaining the finer details about punctuation and typography. It's important we all work to the same standard — even if that means that we have a punctuation rule that's a little different to the advice your English teacher gave you in school.
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