Su meaning your!
I´m doing the Rosetta Stone courses and this has come up..
donde está mi periodico? su periodico está encima de la mesa
Now I know that "su" in this context means "your", but I dont know why! And for future learning I really wanna know why and how this works. A Spanish friend told me it was because it relates to usted and su meaning ownership, but that does nothing for me. Can anyone help me understand why its not tu or usted instead of su?
'tu' is the familiar possessive adjective in the 2nd person, so, in your example, 'su' is the formal possessive adjective in the 2nd person.
Point is, if you know somebody really well, or they are younger than you, you can use 'tu' for 'your', conversely, if you don't know them well, or they are older than you, use 'su' for 'your'.
Good luck with your Rosetta Stone courses. I've gone through 5 levels of RS Latin American Spanish. You've just discovered one of the 'weaknesses' of RS, grammar. This site is a wonderful supplement to RS or a great stand alone resource.
Welcome to the forum. Su is the 3rd person possessive adjective. You can learn about those in this page from our Reference Section.
Also, be sure to use proper punctuation (including capitalization) when posting here. We have those who are learning English, and that makes it important for them.
¡Hola Bético! Your question reminded me of hundreds of similar questions that I asked when I first began learning Spanish. I learn best by connecting new things to what I already know. I need reasons. And you will find that there are good reasons for many of the Spanish words, phrases and sayings we use.
However let me warn you, to save yourself a lot of frustration, it is good to accept that some words are what they are, just because. There is undoubtedly a book somewhere that explains the etymology of the word "Su". But don't stop progressing until you can understand what that is. I think you'll find it easier to accept that "Su libro." can mean "your book", "her book", "his book", or "their book".
You'll also find that the reference that Goyo already cited is really helpful. As are all the other features of SpanishDict.
We look forward to seeing you around!
this site is more than wonderful .