1. If the letter before the "y" is a consonant:
* Change the "y" to "ies".
* Example: baby - babies, fly - flies, story - stories
2. If the letter before the "y" is a vowel:
* Simply add an "s".
* Example: boy - boys, monkey - monkeys, toy - toys
Exceptions:
* Some nouns ending in "y" have irregular plurals, like:
* baby - babies
* penny - pennies
* lady - ladies
* Proper nouns ending in "y" usually follow the rule of adding "s":
* Mary - Marys
* Henry - Henrys
Note:
* This rule applies to nouns ending in "y". It does not apply to words ending in "ey" (which are usually formed by adding "s").
* Example: donkey - donkeys, key - keys