Punctuation with "sino"

Question

I'm using a "learn Spanish" app on my phone to refresh my memory and get some practice, and I have a question about what one of the lessons is teaching.

It's a lesson on conjunctions, and it has several sentences using sino. A few examples:

No quiero leche sino agua.

No camino sino corro.

Now I understand what these sentences mean, but I'm confused regarding punctuation. If I were to write them in English myself, I would say:

I do not want milk; rather/instead I want water.

I do not walk; rather/instead I run.

The app displays the proper English translation once I've tried to input it, and it says the following is correct:

I do not want milk, but rather water.

I do not walk, but rather I run.

Okay, so aside from the rather vs but rather difference, I'm confused on the punctuation. I'm dubious of the comma in their English version (I think it needs the semicolon) but either way, there is some form of punctuation before (but) rather in the English version, and none before sino in the Spanish version. Is this correct? If so, can someone explain why? I actually got one of these constructions wrong on my first try, because I had trouble parsing the sentence with the lack of punctuation. So any insight into the matter would be appreciated!

Answer 1

While my source is not as authoritative as the DPD, this blog explains a case that is not covered by Chewis's answer.

Sometimes the term uses comma, sometimes not.

With comma when confronting a positive element to a negative one, or in no sólo …, sino también clauses.

No quise decir eso, sino todo lo contrario.

No solo toca la guitarra, sino también el piano y el violín.

Translates

I did not mean that, but just the opposite.

Not only plays guitar, but also piano and violin.

Without comma when meaning except, but only:

No amo a nadie sino a Fernando.

No pido sino que escuchen lo que tengo para decir.

Translated

I do not love anyone but Fernando.

I ask nothing but to be listened in what I have to say.

According to your examples I would not use the comma as it introduces an uneasy pause, even if they are contrasts:

No quiero leche sino agua.

No camino sino corro.

But I would use a comma if I make the second part into a subordinate sentence:

No quiero leche, sino que prefiero agua.

No camino, sino que corro.

Contrast in English:

I don't want milk but water.

I don't want milk, but rather water.

Answer 2

You are right in your suspicion. Compound sentences using adversative conjunctions need a comma between the simple sentences, as explained in the article for coma from the Diccionario Panhispánico de Dudas:

1.2.8. Se escribe coma delante de las conjunciones o locuciones conjuntivas que unen las oraciones incluidas en una oración compuesta, en los casos siguientes:

a) Ante oraciones coordinadas adversativas introducidas por pero, mas, aunque, sino (que): Hazlo si quieres, pero luego no digas que no te lo advertí.

So it should read:

No quiero leche, sino agua.

In fact, there's a second mistake in your second example. It should have a que after sino (source).

No camino, sino que corro.

Answer 3

My Spanish isn't that good, probably low intermediate at best, but I've been speaking English all my life, and though I don't have an English degree, I've addressed the English portion of your question a couple of times outside of this forum, so I'll attempt to answer that portion of your question here now. In fact, why recreate the wheel, I'll just paste what I've already written below:

I am familiar with the rule about adding a comma before a conjunction in a compound sentence, but, at least in American English, the rule is optional when the independent clauses of the compound sentence are short. So that you don't have to take my word for it, I have included an excerpt from a book titled, The Best Punctuation Book, Period: A Comprehensive Guide for Every Writer, Editor, Student, and Businessperson:

"When independent clauses joined by a conjunction are short and clear, the writer has the option of not using a comma." Examples given are as follows:

"Jane likes pizza and she also likes pasta."
"You could stay or you could go."
"I walked there but I ran home."
"Vegetables are packed with vitamins and that's important."
"Pack your things and go."