Spelling Rules -- Making Noun Plurals - Page 6
Rule 16: Some nouns exist both as pairs and without pairs. Some examples are:
1. glasses (eye glasses) - pair of glasses 2. spectacles (eye glasses) - pair of spectacles
Question: Some people refer to their children as a pair of twins.
If twins are two people is a pair of twins four people? And those with two pairs of twins 8 people?
Rule 17: The plurals of some nouns are formed by the change of letters within.
1. woman -- women 2. man -- men 3. foot -- feet 4. tooth -- teeth 5. goose -- geese 6. mouse -- mice
Rule 18: A few plurals of some words end in en or ren.       1. ox -- oxen     2. child -- children