The document discusses the use of hyphens in English to join words and avoid confusion. It outlines seven main functions of hyphens: 1) in compound numbers and fractions, 2) with compound nouns, 3) with coequal nouns, 4) with compound modifiers, 5) in phrases used as modifiers, 6) with prefixes and suffixes, and 7) to avoid awkward letter combinations that could cause confusion. Hyphen guidelines are provided for each function, such as using hyphens for compound numbers like twenty-one and compound modifiers preceding nouns like middle-class family.