Comma splice

A comma splice is the use of a comma to join two independent clauses. For example:

It is nearly half past five, we cannot reach town before dark.

Although acceptable in some languages and compulsory in others (e.g. Bulgarian or French), comma splices are usually considered style errors in English. Some English style guides consider comma splices appropriate in certain situations, such as when being poetic or with short similar phrases.

The original 1918 edition of The Elements of Style by William Strunk Jr. advises using a semicolon, not a comma, to join two grammatically complete clauses, except when the clauses are "very short" and "similar in form", for example:

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.

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 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.

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