Is this sentence acceptable?
You’re welcome, have a nice day ahead.
It depends on who you ask. Some people think comma splices are always unacceptable, while others think that they can even be stylistically better choices in some circumstances.
The article in Wikipedia is very useful:
Comma splices are [in the main] condemned in The Elements of Style, a popular American English style guide by E.B. White and William Strunk, Jr.
According to Joanne Buckley, comma splices often arise when writers use conjunctive adverbs to separate two independent clauses instead of using a coordinating conjunction. A coordinating conjunction is [often considered to be] one of the seven words: for, and, nor, but, or, yet, so. A conjunctive adverb is a word like furthermore, however, or moreover. A conjunctive adverb and a comma (or a conjunctive adverb between two commas) is not strong enough to separate two independent clauses and creates a comma splice; only semicolons and periods are strong enough to separate two independent clauses without a conjunction. For example, the following sentence contains a comma splice with a conjunctive adverb:
There is no admission fee, however, you will be responsible for any food you order.
Grammarians disagree as to whether a comma splice also constitutes a run-on sentence. Some run-on sentence definitions include comma splices, but others limit the term to independent clauses that are joined without punctuation, thereby excluding comma splices.
Strunk & White notes that splices are sometimes acceptable when the clauses are short and alike in form, such as:
The gate swung apart, the bridge fell, the portcullis was drawn up.
The famous sentence I came, I saw, I conquered falls into the same category.
Fowler (third edition, 1996) notes a number of examples by reputable authors:
'We are all accustomed to the … conjoined sentences that turn up from children or from our less literate friends… Curiously, this habit of writing comma-joined sentences is not uncommon in both older and present-day fiction. [More modern examples]:
I have the bed still, it is in every way suitable for the old house where I live now (E. Jolley);
Marcus … was of course already quite a famous man, Ludens had even heard of him from friends at Cambridge (I. Murdoch).'
The comma splice is often considered acceptable in poetic writing. The editors of the Jerusalem Bible translate Isaiah 11:4 as:
His word is a rock that strikes the ruthless, his sentences bring death to the wicked.
The British author Lynne Truss observes: "so many highly respected writers observe the splice comma that a rather unfair rule emerges on this one: only do it if you're famous." She cites Samuel Beckett, E. M. Forster, and Somerset Maugham. "Done knowingly by an established writer, the comma splice is effective, poetic, dashing. Done equally knowingly by people who are not published writers, it can look weak or presumptuous. Done ignorantly by ignorant people, it is awful."
Comma splices are considered acceptable by some in passages of spoken (or interior) dialogue and are sometimes used deliberately to emulate spoken language more closely.
The last points certainly cover the example "You're welcome, have a nice day." But I think that "You're welcome – have a nice day!" conveys better how I'd say it (or want to hear it – the comma indicates brusqueness, a throw-away platitude, to me).
A comprehensive and balanced overview is given here:
Before I start explaining what a comma splice is and how to correct one, I want to make it clear that not all comma splices are errors.* Unfortunately, few American English teachers are aware that there is a type of comma splice that is perfectly acceptable, and so they mark all comma splices as errors.
If you have read some of my other articles on grammar and usage, you know that there are certain "rules" that need not be slavishly obeyed. I don't recommend gratuitously splitting an infinitive or ending a sentence with a preposition, simply because so many people are likely to jump on you when you do. However, when the occasion clearly calls for either a split infinitive or a preposition at the end of the sentence, I say go for it. But even when a properly handled comma splice would produce just the rhetorical effect I am after, I won't use it.
No doubt you are disappointed in me. The fact is, though, that in the U.S. a lot of people who are sure they understand the "rules" of English firmly believe that all comma splices are not just errors, but really big errors, and that any one who commits a comma splice is demonstrating a fundamental inability to control a sentence. If I were to use a perfectly acceptable comma splice, I can be sure that an awful lot of people would assume that I have no mastery of sentence boundaries. They would be wrong, but I would never get the chance to argue the point, so their judgment would stand.
Sometimes it seems that the rule against comma splices is the only rule that many people--English teachers especially!--have managed to master, and so they are always on the hunt for an opportunity to wield it against someone. While it is true that in American usage most comma splices are errors, it is also true that some are worse errors than others, and some are not errors at all.
I am not even sure it is considered a matter of concern in British usage, and if any of my readers are from the U.K., I would like to know whether current usage there abhors the comma splice as does American usage.
Now to business.
WHAT IS A COMMA SPLICE?
Quite simply, a comma splice is the attempt to join two independent clauses with a comma, but without a coordinator.
Let's back up for a moment. First of all, according to the definition most of you learned in grade school, an independent clause is one that can stand alone as a sentence. (This is not the most precise or useful way to define an independent clause, but it will do for now.) When two independent clauses are next to each other, you have only two choices: you can either join them, or you can separate them.
(1) To join two independent clauses, you must use a coordinator. The coordinators are the correlatives and the coordinating conjunctions. (Correlatives don't figure into comma splices, so we will not worry about them.) The coordinating conjunctions are and, but, or, nor, yet, and so. You can remember them by combining their first letters into the pseudoword "anboys." Your English teachers and your usage handbooks also listed "for" as a coordinating conjunction. Forget that. As a conjunction "for" translates as "because," and serves as a subordinating conjunction, just as "because" does.
(2) To separate two independent clauses, you must use some form of end-stop punctuation. Here are all of your possible choices: the period [.], the exclamation point [!], the question mark [?], and the semicolon [;]. (Remember, a semicolon is a weak period, not a strong comma. The semicolon fragment is a common error, one I deal with in "Colons, and Semicolons, and Bears!")
What this means is that if you have two independent clauses with nothing between them but a comma, you have failed either to join them with a coordinator or to separate them with end-stop punctuation. (You will notice that the comma is not on either of those two lists.) Thus, you have a comma splice, which is a form of run-on sentence.
Here is an example of a comma splice, followed by several different ways of correcting it:
COMMA SPLICE: I got up late this morning, I didn't have time for breakfast.
I got up late this morning. I didn't have time for breakfast.
I got up late this morning; I didn't have time for breakfast.
I got up late this morning, so I didn't have time for breakfast.
I got up late this morning, and I didn't have time for breakfast.
Notice that in the latter two corrections, the coordinating conjunction joining the two independent clauses is preceded (not followed) by a comma. (That's about a 90-95% rule. See "Commas with Compound Sentences" for information about when that comma can be omitted.) What causes a comma splice is not the comma between the two clauses, but rather the absence of the coordinator in the attempt to join the clauses.
A DIFFERENT STRATEGY: If you choose to turn one of the clauses into a subordinate (dependent) clause, then you can use just the comma between the two clauses:
Because I got up late this morning, I didn't have time for breakfast.
When Is a Comma Splice NOT an Error?
by Tina Blue August 25, 2000
NOTE: Unless you already know what a comma splice is and why it is usually considered an error, please read my article "What Is a Comma Splice, and How Do I Fix It?"The current article might be confusing if you do not read that one first.
Barbara Wallraff, who writes the delightful "Word Court" column on the back page of The Atlantic Monthly, has recently published a book on the correct use of language. The book's title is the same as her columns, so I'm guessing, as I've not seen the book yet, that it is a compilation of "Word Court" columns.
The current Quality Paperback Book catalogue quotes from her a wonderful line about comma splices--"Take this sentence, for example: 'It's not a comet, it's a meteor.' According to Wallraff, 'punctuating this sentence with a semicolon would be like using a C-clamp to hold a sandwich together.' "
There are times when a comma splice is a justifiable stylistic device, not an error.
ACCEPTABLE COMMA SPLICES
~1. If the independent clauses are very short, especially if the subject is the same for both clauses, then a comma splice is probably acceptable.
I came, I saw, I conquered.
~2. When fairly short independent clauses express contrast, a comma splice is often the most effective way to punctuate the sentence. This is especially true if the first clause makes a negative statement, the second an affirmative one, or if the first clause is affirmative, and the second is negative (as in one form of question).
~This is my father, that is my uncle.
~Some students find writing easy, some find it excruciatingly difficult.
~It's not a comet, it's a meteor.
~We aren't visiting Pennsylvania this year, we're spending the summer in Florida.
~You saw that movie last night, didn't you?
~It looks as though we're in for a tornado, doesn't it?
~You've been to Europe, haven't you?
Ironically, many pedants who declare death to all comma splices do not even recognize the comma splices in those last three sentences, but if you check the definition of a comma splice, they certainly fit.
But--just as in my article "What Is a Comma Splice, and How Do I Fix It?"--I must warn you that it is usually better to restructure a sentence to avoid even a justifiable comma splice, simply because so many teachers, editors, and readers don't understand the issue well enough to realize that you have not made an ignorant error.
Sure, you could strike a blow for reasonable usage, but those people are going to be judging you harshly, and you may not have the opportunity to argue the correctness of your sentence. Besides, in my experience there is nothing harder than trying to argue a pedantic know-it-all out of a rule he believes to be all-encompassing. I save my energy for less frustrating, more productive pursuits. (Of course, since the comma splice cops don't even recognize questions like the last three examples as comma splices, you can safely use such sentences without fear that you will be sneered at.)
Another point in favor of avoiding even acceptable comma splices is that many writers routinely make comma splice errors, so only the most sure-footed should attempt to negotiate such rocky terrain. If you aren't absolutely sure about what is right and what is wrong in comma usage, it's probably not a good idea to attempt an acceptable comma splice, because you might end up with a comma splice error after all.