In a sentence like His name is Joseph, but you can call him Joe the names Joseph and Joe are not used 'referentially' (to name a certain male individual) but just 'mentioned', i.e., they are used 'metalinguistically' to refer to themselves. Otherwise, of course, such sentences would be nonsensical, as Quine explained long ago, and, for that reason, I instinctively enclose them in quotation marks whenever I have to write sentences like that.
Yet, as far as I know, at least in English (but also in Spanish, German, French, Italian,... Mandarin) they are not orthographically treated as metalinguistic expressions at all. I mean, they are never enclosed in quotation marks or otherwise marked as cases of 'mention' rather than ordinary referential 'use', are they? Does anybody know why? Are there languages out there in which parallel names in equivalent sentences would be orthographically marked, via quotation marks or similar devices, as cases of metalinguistic, rather than ordinary referential use?