¡I love the Spanish upside-down exclamation and question marks! ¿Don’t you?
I’m serious. In fact, when taking notes or otherwise writing by hand (pretty rare these days), I use ¡ and ¿ in my English. Both marks give the reader a useful heads-up that a text is about to depart from simple declarative prose. It’s surprising that ¡ and ¿ haven’t caught on beyond Spanish — not even in Catalan or Portuguese.
This “heads-up” function motivated the Real Academia, or Spanish language academy, to invent the inverted marks in the first place, back in 1754. Thirteen years earlier, the Academía had published its first Ortographía, or spelling guide, of the Spanish language (the title was modernized to Ortografía in all later editions). The 1741 Ortographía proposed that normal ! and ? marks do double duty to mark both ends of exclamations and questions, as in ?quien me llama? or !que misericordioso es Dios! (p. 266).
Not surprisingly, this idea appears to have been a dismal failure. When the Academia’s spelling committee reconvened in 1754, they proposed today’s ¡ and ¿ marks instead, explaining (my translation):
The hard part was deciding on a punctuation mark. If we were to employ one already used for accents or other purposes, it would be confusing [a reference to the 1741 proposal???]; to invent a new mark would be risky, and perhaps not accepted. Therefore, after long consideration, it occurred to the Academy that we could use the question mark itself, putting it upside down before the first word of the question, as well as right side up at its end….[In the case of exclamations] we will use the same exclamation mark (Nota de Admiración), putting it upside down before the first word of the exclamation. (pp. 126-9)
The second time, they got it right, thus providing one of the world’s few examples of successful linguistic innovation by committee.
[Note to the picky reader: the image above is actually from the 1763 edition of the Ortografía (p. 140), which uses the same wording as the 1754 edition but is much more legible.]