It’s because Spanish sentence structure is different from English. In Spanish the sentences “Can I tell you? (¿Te lo puedo decir?) and “I can tell you.” (Te lo puedo decir.) are formed the same way. The initial punctuation lets the reader know that the sentence is a question or exclamation or not so they can parse the sentence properly from the start.
Sentence structure likely plays a role but, at the end of the day, it's just a spelling convention - people do it because they do it. And it's generally absent from the standard orthography of Portuguese and Italian, even if they're syntactically similar to Spanish (i.e. no German/English-like VSO for questions).
Yeah, it's just tradition at this point, though I feel like native speakers really try to oversell its usefulness when someone questions if the opening signs are necessary. People act like they routinely need to read text written like the Cartas de relación out loud, and thus, need the additional warning lest they get lost in the long, multi-clause sentences. Like, I could understand if you had to read something like
Y después acá, por no haber oportunidad, así por falta de navíos y estar yo ocupado en la conquista y pacificación de esta tierra, como por no haber sabido de la dicha nao y procuradores, no he tornado a relatar a vuestra majestad lo que después se ha hecho; de que Dios sabe la pena que he tenido. Porque he deseado que vuestra alteza supiese las cosas de esta tierra, que son tantas y tales que, como ya en la otra relación escribí se puede intitular de nuevo emperador de ella, y con título y no menos mérito que el de Alemaña, que por la gracia de Dios vuestra sacra majestad posee. Y porque querer de todas las cosas de estas partes y nuevos reinos de vuestra alteza decir todas las particularidades y cosas que en ellas hay y decir se debían, sería casi proceder a infinito.
out loud on a regular basis, but even contemporary literary Spanish doesn't tend to have nearly the same amount of sentences that just go one for half a page, much less the sort of stuff people would write to each other normally.
As you've mentioned, other syntactically similar languages do just fine without them, even including other Romance languages spoken in various regions of Spain. The only exception I'm aware of is Asturianu, which apparently also uses them, though apparently they're optionally allowed in Galego Real Academia Galega. On page 38 of the PDF, it says they're entirely optional if you want to facilitate reading by including them.
Sure they are not strictly necessary, but nice to have. It's like how we capitalizing the first word of every sentence in English. Really helps guide the eye.
Well now I have to wonder why other languages don't do the front punctuation thing. It would be just as helpful in English as it is in Spanish to know a sentence is a question before getting to the end of it. Scrambling to lift your voice into a question you've been reading as a statement until you see the question mark at the end is awkward. lol
Scrambling to lift your voice into a question you've been reading as a statement until you see the question mark at the end is awkward
I'd argue this is exactly why it's not necessary on English; what makes it a question tends to be the inflection at the very end so no real need for a warning way at the beginning.
Also, while English certainly can form questions that are identical to statements ("They fly now?" "They fly now."), it's not necessary or even the most common way. More of the burden for clear communication can be left to the writer.
English changes the order of the words of the sentence. Spanish uses punctuation marks. It’s just differences in languages. Personally I appreciate them since it helps me read Spanish quicker with fewer parsing errors.
Dunno for others but for me this question sounds rhetorical, due to the lack of inversion. By default you expect questions in English to start with an optional interrogative pronoun, plus a [typically auxiliary] verb - "can I tell you?", "do you know him?", "how do you know this?" et cetera.
English, you mean that notoriously easy to parse and learn language that has rules so obscure that native speakers don't even realize they're adhering to them? Tell that to my Irish old small lovely mother.