Why is 'se' necessary?
La niña se ríe.
Why do I need the 'se' in that sentence? It translates to the girl she laughed. Why not just say La nina rie? The girl laughed.
I've seen other sentences that have the word 'se' in them. They don't seem to be referring to a reflexive verb. It seems like it gets thrown in there as a redundancy but I'm having difficulty translating it for my own edification.
Thanks in advance!
10 Answers
What a great question!
You are correct that a lot of the time the reason for reflexive is obvious to us who are learning Spanish, in that we can relate to the concept of the action occurring to "self".
However, once in awhile, a verb comes along, such as "reírse" which doesn't make too much sense for those of us who are thinking along English lines. The proper translation is "to laugh", and you are correct that it is a reflexive verb.
I know I didn't really answer your question, but sometimes language things are a certain way "just because", and this is one of those cases.
As a native speaker I don't have a technical explanation for this, just the certainty that BOTH sentences are all right.
The girl laghs La niña ríe o La niña se ríe
The girl laghed La niña rió o La niña se rió
"Se" is the reflexive pronoun, it means the verb is acting on herself. She is the subject and the object.
In all cases, the presence of the "se", or whatever reflexive pronoun is appropriate, changes the sense of the verb. My favorite example is the difference between "sentir" and "sentirse" where the first would usually be due to an external influence (sentir calor) and the later would be how you (or the person in question) feels inside (sentirse triste).
In the question of reír vs reírse, I believe the best approximation is: reír by itself refers more to the laughter, and reírse has more to do with the person laughing (or the person being laughed at).
Yo me río. I laugh. I am what's important. Reír a carcajadas. Laugh like crazy. The laughter is what's important.
Using reír by itself is relatively rare, afaik.
In everyday life you can use both... there's no difference. Another good example is:
Ayer murió Juan... o Juan murió mientras trabajaba
Ayer se murió Juan.... o Juan se murió mientras trabajaba
There's NO difference
Hope it helps!
It makes the sentence intransitive rather than transitive.
La chica rió "No voy a hacerlo".
La chica se rió.
So it could be translated as "she laughs herself?" or in the case of "los ninos se rien", "they laugh themselves"?
Hi elsalsero! You have asked a question that just may be the most difficult to understand and explain. (Did you notice that one of the answers is from 'Benz'? She is a native speaker and a professional translator, but admitted not having 'a technical explanation'.)
There have been some great answers already. If you are really serious about understanding this topic, you will find the following older thread very interesting.
http://www.spanishdict.com/answers/3342/how-do-you-explain-se-why-is-in-the-sentences/oldest
It is rather lengthy, but worth reading through to see how the explanations develop throughout. Take special note of comments made by a user named Lazarus1907. He has the understanding of a native speaker, and can explain grammar in an easy to understand way.
And if you can read Spanish, then this link will also be helpful:
I hope that helps! 
,, se 'in Spanish is a pronoun return - a. Defines a person. Similarly, in the case LLAMARSE or ACOSTARSE.
This is a great question.
Is there a subtle difference like she is laughing at something she thought? Or that she is laughing at something that she saw?
