This document discusses rules for making words plural in English. It explains that most words become plural by adding -s, but there are exceptions. Words ending in ch, s, sh, or x add -es. Words ending in y drop the y and add -ies, unless the letter before y is a vowel when only -s is added. Words ending in f drop the f and add -ves, but some just add -s. The document also notes some irregular plurals from Latin words ending in a, um, and us.