Using Hyphens and Dashes
Word automatically changes some hyphens into em- and en-dashes (an em-dash, as the name implies, is the width of a lowercase m, and an en-dash is the width of a lowercase n). For example:
Type a letter, followed by two hyphens, followed by another letter, and Word changes the hyphens to an em-dash. It's nicely done, because the em-dash has a little bit of space to the left and right, and a line can break before or after an em-dash.
Type any letter, followed by a space, a hyphen or two, and any other letter, and Word transforms the hyphen(s) into an en-dash.
This behavior is controlled by Word's AutoFormat As You Type feature.
→ For instructions on how to disable this and other AutoFormat options, see "Disabling AutoFormat Settings".
In addition, you can always type an em-dash into a document by pressing Alt+Ctrl+- (minus) on the Number pad. An en-dash is Ctrl+- (minus) on the Number pad.
Caution
Don't use the - (minus, or hyphen) that's to the right of the zero on most keyboards. If you accidentally hit Alt+Ctrl+- (to the right of the zero), check the "Troubleshooting" topic at the end of this chapter called "Removing Menu Shortcuts."
→ For instructions on how to customize keyboard shortcuts for dashes and other characters, see "Bypassing Menus with Keyboard Shortcuts".
As your columns become more narrow, good hyphenation becomes crucial to minimize the vast expanses of whitespace that characterize unhyphenated or poorly hyphenated text. Word offers three different methods for hyphenating:
Automatically— Most experienced Word users who work in Print Layout view avoid this method because the constant sliding of lines makes it hard to concentrate on the screen. To turn on automatic hyphenation, choose Tools, Language, Hyphenation. In the Hyphenation dialog box (see Figure 15.7), click the Automatically Hyphenate Document box. Hyphenation takes place immediately when you click OK, and Word continues to automatically hyphenate as you type or edit text. The Hyphenation Zone is the maximum allowable whitespace at the end of a line; the Limit Consecutive Hyphens To box specifies the maximum number of consecutive lines that can be hyphenated.
Figure 15.7.
Manually, Whole Document— Choose Tools, Language, Hyphenation, and then click the Manual box. Word steps you through each hyphenation, allowing you to accept or reject each.
Note
Generally, you'll want to undertake a manual hyphenation only after the text is in its final form. Making any changes to the text will probably throw off the hyphenation, at least in any changed paragraphs.
Manually, One Word at a Time— You needn't turn on automatic hyphenation to have Word hyphenate an occasional word. Instead, use a "soft" or "optional" hyphen by clicking where you want the soft hyphen to appear, and then pressing Ctrl+-. Word uses the hyphen if it's required to balance out the line; if not, the hyphen won't appear.
Sometimes you want to prevent Word from breaking a line at a hyphen. For example, the word CD-ROM should never be broken. Tell Word that you don't want it to break at that point by using a "hard" or "nonbreaking" hyphen: Ctrl+Shift+-.
Tip from 
Word will not hyphenate paragraphs that have either of two types of formatting. In the Paragraph dialog box (choose Format, Paragraph), you can check the Don't Hyphenate box. Or in the Language dialog box (choose Tools, Language, Set Language), you can check the Do Not Check Spelling or Grammar box.