This document provides rules for making words plural in English. It explains that some words simply add "s" to become plural, such as boy becoming boys. Words ending in "ss", "sh", "ch", and "x" add "es", like glass becoming glasses. Some words ending in "o" add "es", like potato becoming potatoes. Words ending in "y" usually drop the "y" and add "ies" to become plural, except for words ending in a vowel and "y" which simply add "s", like day becoming days. The document provides examples of each of these pluralization rules.