Writeability

To pluralize nouns that end with -fe change f to v then add -s

• Example: knife - knives
  

To pluralize nouns that end with -f  change f to v then add -es

• Example: wolf- wolves 
  

To pluralize nouns that end with -o  add -es

• Example: potato - potatoes
  

To pluralize nouns that end with -us Change -us to -i

• Example: nucleus - nuclei
  

To pluralize nouns that end with -is Change -is to -es

• Example:crisis - crises
  

To pluralize nouns that end with -on Change -on to -a

• Example: phenomenon - phenomena

To pluralize some words irregular endings are required

• Example: mouse - mice

Some words are unchanged when either singular or plural

• Example: sheep

Some singular words are completely different words when pluralized

• Example: person - people

To pluralize some singular words the vowel must be changed

• Example: tooth - teeth ; man- men

When pluralizing words do not use - 's