‘Words for punctuation,’ Lynne Murphy writes in her new book The Prodigal Tongue, ‘offer a neat little laboratory for viewing the possible fates of migrating words.’
When North America was being settled, norms of punctuation, including the marks’ names, were very much in flux. So when things stabilized, the names in the US and the UK sometimes differed. Certain marks, such as the comma and question mark, acquired the same name in both regions; others, such as the full stop (period, full point), diverged.
The latter group also includes quotation marks, aka inverted commas. But the facts are more complicated – and therefore more interesting – than is generally supposed. Here’s Murphy: