Plurals (Levels 8-1 to 8-4)
Levels 8-1 through 8-4 all focus on plural nouns. Level 8-1 focuses on words that either add -s or -es to the end when they become plural. The ten words used in this level are guesses, doors, glasses, symbols, potatoes, dresses, flowers, seeds, valleys, and taxes. As a general rule, nouns ending in -ch, -sh, -ss, and -x will add -es when becoming plural. The oddball word in this group is 'potatoes,' the spelling of which once famously led a certain vice president to misspell the singular form of that word.
Level 8-2 focuses on two types of plural patterns: y --> ies and f --> ves. The ten words in this level are ponies, babies, loaves, shelves, knives, lives, stories, ladies, copies, and parties. When a noun ends with a consonant and then a 'y', typically that 'y' drops and is replaced by 'ies' when the word is made plural. When a noun ends in a single 'f', most of the time the 'f' drops and is replaced by 'ves.' Some exceptions to this rule exist, however (chief, roof).
Level 8-3 focuses on irregular plurals. The ten words in this level are children, women, teeth, mice, feet, people, men, geese, sheep, and deer. Finally, level 8-4 reviews all of these types of plural nouns. The ten words used for that level are puppies, kisses, wishes, wolves, elves, families, churches, volcanoes, boxes, and heroes.