Daniel Kies Department of English College of DuPage
Modern English Grammar English 2126		Contact Form

Comma Splice

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Introduction to the problem

Comma splice, occasionally called comma fault in some handbooks, occurs whenever a writer uses only a comma between two independent, main clauses, such as in I have a story, it's an escape story. Comma splice is a punctuation problem that has sentence-level implications.

The comma is among the most frequently used marks, so it is not surprising that it plays a role in so many of the top twenty usage errors. The comma splice error, however, is among the most stigmatized of usage errors, often bringing ridicule and scorn from readers. The comma splice is relatively easy for readers to spot; therefore, this error deserves special attention when proofreading.

Examples

Examine the sentences below and see if you can find the comma splice in each sentence. Then hover your mouse over the sentences to see my comments about the problems illustrated by each example.

1. I'll be careful, I promise.
2. In 1980, Reagan promised to balance the federal deficit, however by 1988 the deficit was the largest in U. S. history — until now.
3. I will revise the schedule, after all, I don't like it either.
4. Wild Bill likes drinking, gambling, and women, I think he must have an interesting life.
5. John promised to return the tools, he borrowed from the workbench.

Discussion

In my experience, these are the most common reasons writers create comma splices.

Short main (independent) clauses

It seems that some writers try to avoid writing short, independent clauses. Perhaps, the thinking is that sentences must be longer, multi-phrased constructions to be truly sentences. Hence, some writers seem to prefer to join short independent clauses, as in example (1) above instead of writing I'll be careful. I promise.

Confusing adverbs as conjunctions

Writers sometimes confuse some adverbs, such as furthermore or however for conjunctions, especially coordinating conjunctions, such as and or but. The causes for that confusion make sense for several reasons. First, notice that some adverbs share semantic similarities with some conjunctions. For example, consider the following sentences.

6. I passed the exam, and Mary did too.
7. I passed the exam; furthermore, Mary did too.
8. I like Bob, but he doesn't like me.
9. I like Bob; however, he doesn't like me.

Both and and furthermore express a sense of addition, while both but and however express the idea of a contrast between the two clauses.

Second, notice too that these adverbs and conjunctions appear to be in the same position — between the two main, independent clauses — in examples (6) through (9).

Therefore, it does not seem surprising that some writers would conclude that

• if they have the 'same meaning' and
• if they occur in the 'same place,'
• then the punctuation used for conjunctions (the more common and or but) would be the same punctuation used for the others, the adverbs, too.

Following that reasoning, some writers would punctuation (6) though (9) as we see below, creating comma splices in (11) and (13).

10. I passed the exam, and Mary did too.
11. I passed the exam, furthermore Mary did too.
12. I like Bob, but he doesn't like me.
13. I like Bob, however he doesn't like me.

Confusing prepositions as conjunctions

Words often have more than one meaning and use. This is not uncommon in any language. In English, many words can function both as prepositions and conjunctions. Consequently, writers often confuse the prepositional use of a word with its use as a conjunction. Then writers punctuate the preposition as if the word were a conjunction and make a comma splice error inadvertently. Consider examples (14) through (17) below.

14. I worked on my project until the phone rang.
15. I worked on my project; until then, everything was quiet.
16. We watched TV, before we fixed the bike.
17. We watched TV; before that, we fixed the bike.

Note that it is optional to have a comma before the conjunctions in (14) and (16).

In (15) and (17) above, we see the prepositional uses of until and before. If a writer were to misinterpret the functions of those two words, s/he might punctuate them as if the prepositions were conjunctions as in (14) and (16). The result would be comma splice errors as in (18) and (19) below.

18. I worked on my project, until then, everything was quiet.
19. We watched TV, before that, we fixed the bike.

The comma is among the most frequently used marks, so it is not surprising that it plays a role in so many of the top twenty usage errors.

Elaborated 'comment clauses'

A writer will occasionally add small clauses into a sentence. These clauses add a comment on the writer's attitude toward the subject under discussion. For example,

20. Bill is, I think, the best worker.
21. The Democrats will, some say, have a hard time winning in November.
22. Newspapers are having a hard time making a profit, you know.
23. Country people need more political support, she thought.

Comment clauses often (but not necessarily) are two word constructions (as we see above), can appear sentence-medially or sentence-finally, and are punctuated with commas. Sometimes, comment clauses are elaborated slightly, as in (24) and (25).

24. Bill is, I think you could say, the best worker.
25. Newspapers are having a hard time making a profit, you know what I mean.

If the comment clause elaboration comes at the end of the sentence, as in (4) or (25) above, the comment clause could easily be interpreted by the reader as a comma splice.

Incorrectly reducing relative clauses

Relative clauses are common postmodifiers of noun phrases. Relative clause can be reduced in form by eliding some of its forms. Also, relative clause reduction can occur to different 'degrees,' meaning that sometimes just the relative pronoun is elided, as in (26). Sometimes, the relative pronoun and the auxiliary verb are elided, as in (27).

26. The book that he read was interesting.
27. The cat that is running away is scared.

Note too that noun phrases with relative clause postmodifiers can appear sentence-initially, -medially, or -finally, as in examples (28) through (30). (The noun phrase is in italics, and the relative clause is in bold face.)

28. The book that he read was interesting.
29. The woman ordered the book that he read from a local book shop.
30. I too like the book that he read.

Note too that a comma is traditionally used with a non-restrictive relative clause functioning as a postmodifier, as in (31) below.

31. I too like that book, which he read too.

Now, consider this situation: if a writer thought that a relative clause, as in (32), were the equivalent of the relative clause in (33) and reduced that relative clause on the basis of an example like (26), s/he might produce an inadvertent comma splice as in (5) above or (34) below. Many writers fail to distinguish between restrictive and nonrestrictive relative clauses. For such writers, reducing a non-restrictive relative, like (33) in a manner analogous to (26) or (32), produces a comma splice, as in (34).

32. I too like the book that he read.
33. I too like the book, which he read too.
34. I too like the book, he read.

Asyndetic Coordination

A special case, syndeton is a rhetorical figure which omits the conjunction. With asyndetic coordination, the coordination is implied. Such constructions look like ordinary comma spliced sentences; however, as a rhetorical figure, asyndetic coordination allows writers to emphasize the several parts as equal in some way. Asyndetic coordination implies a parallel between the parts, an equality among the parts. By contrast, ordinary coordination (syndetic coordination) often implies a sequential order, usually a time order (as in I was walking, I tripped, and I fell to my knees. Often asyndetically coordinated elements come in three parts and exhibit parallelism structurally, as in the most famous example from Plutarch, quoting Caesar, "Veni, vidi, vici." ["I came, I saw, I conquered."] (Plutarch's Life of Caesar)

Although it may seem a rare construction, the Oxford English Dictionary records a use of asyndetic coordination in writing as far back as 1589:

35. "I savv it, I said it, I vvill svveare it." 1589, as recorded in Puttenham's English Poesie (1869)

More resources

Aims Community College Online Writing Lab. Comma Splices and Run-Ons/Fused Sentences

Darling, Charles. Run-on Sentences, Comma Splices

The Purdue OWL. Run-ons - Comma Splices - Fused Sentences

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