What is Punctuation?
Punctuation is the division of written language into sentences and sentence parts by means of certain marks or signs. The main purpose of punctuation is to group words into meaningful patterns, so that the writer's intentions are clear. The reader is shown what to take together and what to separate, what the relationships are among the sentence parts, and what is being emphasized. Certain punctuation marks, notably the comma, are often overused. Generally, marks should be inserted only to clarify meaning. For example, "Call Jim when you get a chance" has a different meaning when, the name Jim is set off by commas.
The marks used in punctuation are sometimes related to tones and emphasis used in speaking. However, the relationship between punctuation and speech patterns is not always exact, and punctuation is more of an aid to sight-reading than to oral reading.
Although certain general principles have been agreed on, the rules for punctuation are not clear in every case. For example, it is not always obvious when to use the colon, semicolon, dash, and parenthesis.
In the sentence "The speculator seeks profit; the investor looks to safety and income", it is possible to substitute a dash or a period for the semicolon. In punctuating Try it if you like—but don't effect a miracle, it would be equally correct to use a comma between like and but. The use of the comma is often a matter of personal taste and judgment.
Punctuation can generally be divided into end marks and internal marks. End marks are the period, question mark, and exclamation point. Internal marks are the comma, colon, semicolon, apostrophe, hyphen, and dash. Punctuation marks that occur in pairs are quotation marks, parentheses, and brackets. The ellipsis or suspended dot may appear as either end or internal punctuation.
- Period. The period (•) is used primarily to mark the end of most sentences. It is found at the end of declarative sentences, hortatory sentences, and imperative sentences. (He read the book. Let us read the book. Read the book.*) The period is also used to end a sentence that contains an indirect question. (He asked whether we had read the book.') The period is found after an abbreviation if there is no apostrophe in the abbreviation. (Mr., Inc., m.p.h.; but B'klyn, gov't, and so on.) It is also used before decimals (1.5) and between dollar and cents figures ($3.25).
- Question Mark and Exclamation Point. The question mark (?) is used to end a direct question. (Who read the book!) It is omitted after an indirect question and is sometimes omitted after a request phrased as a question. (Will you please close the door.) The exclamation point (!) is used to indicate surprise, disbelief, or any strong emotion. (What! That's nonsense! That's wonderful Oh! Get out!*)
- Comma. The comma (,) has more different uses than any other mark of punctuation. Basically it is used either to separate or to set off elements of a sentence. These elements can be words, phrases, or clauses. The following are only a few of the many uses of the comma.
- The comma is used before a conjunction introducing an independent clause. (They -went downtown to see the show, but we stayed home.*) However, it is sometimes omitted in a short compound sentence. (They went but we stayed.) The comma is used after a subordinate clause that begins a sentence. (When they decided to go downtown to the show, we stayed home.*) Similarly, any lengthy phrase at the beginning of a sentence is set off by a comma. (After two hours of listening to the conversation, everyone fell asleep.*) The comma is also found between a direct quotation and the rest of a sentence. (He said, "Come here."*)
One of the most important functions of the comma is to separate three or more elements in a series, whether the elements are words, phrases, or clauses. (The weather consisted of rain, wind, snow, sleet, and hail.*) The comma is also used to set off phrases or clauses that add information but are not essential to the main idea. (They went downtown, where it happened to be very crowded, to see the show.*) A clause or phrase that is restrictive, or necessary, to the main idea should not be set off with commas. (The show that they saw was terrible.*)
Among the many other uses of the comma are to set off words, phrases, or clauses used in apposition (Henry, my friend, is coming*); to set off words of direct address (Mrs. Smith, you have been fired*); to separate such words as however, moreover, and nevertheless from the rest of the sentence; and to separate the terms in special constructions such as dates and geographical names. (July 4, 1776. Minneapolis, Minn.*)
- Colon. The colon (:) is used after a statement to direct the attention to what follows. This is usually an amplification, explanation, or illustration implied in the first statement. (Four marks of punctuation have been discussed: the period, question mark, exclamation point, and comma. The main point of the discussion is this: Punctuation is an aid to reading.*) The colon is also used in statements of time (9:15 A.M.), following the salutation of a business letter (Gentlemen:*), and before a lengthy quotation.
- Semicolon. The semicolon (;) is used between two or more independent clauses that are closely related in idea but are not joined by a conjunction. (They went downtown to see the show; tue stayed home instead.*) In such cases a period would make too sharp a break between the related ideas, and a comma would fail to provide the necessary separation. The semicolon can also be used to separate related elements of a sentence when the elements contain commas. (They went downtown, saw a show, and ate hot dogs; but we stayed home, read the newspapers, and went to bed.*)
- Apostrophe. The apostrophe (') is used to signify the possessive case of nouns (the man's shoes, the women's hats, the students' diplomas*). It is also often used to form the plural of letters, numbers, and words referred to as words. (There are two ll's in your account number. Connecticut has two n's. There are too many and's and so's in your letter.*) Finally, the apostrophe indicates the omission of one or more letters in a contracted word. (Don't go near the water.*)
- Hyphen and Dash. The hyphen (-) is used to indicate some compound words (self-confident*) and the continuation of a word from one line to another. It is also used to connect words of a phrase that modifies a following noun. (It's a once-in-a-lifetime experience.*) The dash (—) indicates a sudden shift in thought or a parenthetical thought. (When she came in—if only she hadn't—the alarm went off.*) It is also used to introduce a summary of a series that has just been stated. (Swimming, riding, boxing—these are all good exercises.*) Generally the dash emphasizes what follows. (I like food—except in the morning.*)
- Quotation Marks. The main use of quotation marks (" ") is to enclose direct quotations. (He said, "What are you doing!"*) Quotation marks can also be used to emphasize a word or phrase or to set off slang words or words used in some special sense. (He thought he was a "big shot.'") Finally, quotation marks can be used to set off titles of short works, such as short stories, poems, songs, and magazine articles.
- Parentheses and Brackets. Parentheses (()) can be used to set off parenthetical or explanatory material in a sentence or paragraph. This book (which is very expensive) is not worth reading. Unlike the dash, parentheses do not emphasize what is set off but instead make it seem like an afterthought. Brackets () are used in quotations to enclose material that has been inserted by someone other than the author or speaker. (When he [Hawthorne] is wrong, he admits it.*) Brackets are also used to enclose editorial corrections, technical material within a more general statement, and material that is already enclosed by parentheses.
- Ellipsis. The ellipsis (. . .) is used to indicate the omission of one or more words in a quotation. ("To beor not to be ... is the question."*) When the omission is at the end of a sentence, the ellipsis follows the period.