Drop the 'y' and add 'ies' when:
* The word ends in a consonant followed by 'y'.
* The suffix begins with a vowel.
Examples:
* baby + ies = babies
* fly + ies = flies
* cry + ing = crying
Keep the 'y' and add 's' when:
* The word ends in a vowel followed by 'y'.
* The suffix begins with a consonant.
Examples:
* boy + s = boys
* monkey + s = monkeys
* day + s = days
Exceptions:
* Some words ending in 'y' form their plural by adding 's' even though they end in a consonant followed by 'y'. This is due to historical reasons.
* These words include: * * * *
* * * * * * * * * *
* * * * * * * * *
Other Considerations:
* If a word ends in a consonant followed by 'y' and the suffix begins with a consonant, you need to change the 'y' to 'i' before adding the suffix.
* Examples: * * * *
* * * * * * * * * *
* * * * * * * * *
It's always a good idea to check a dictionary if you're unsure about the correct spelling.