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.
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.
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.
I would assume it's because it leads the reader to what tone to use in a given sentence. The question mark or exclamation point would be useful in tone throughout the whole sentence, but if neither is present in front of the sentence a regular reading tone could be assumed.
so why add a floating period when nothing being there allows for the same assumption and is much, much simpler and easier?
Still learning Spanish but I believe this is correct, because you can insert a question mark into the middle of a sentence as well if the entire sentence isn’t a question.
Language is more than just written script and spoken words - grammar is very language specific too. In Spanish, the example above is indeed grammatically correct.
Yup! I really like it a lot more than how we do it in English honestly, it’s like quotation marks for a question. It’s very pleasing to me to have something in the sentence clearly highlighting what the question is. If it has any annoyances or drawbacks I’m not at a comprehension level where I’ve run into them.