Which sounds at the end of words can be identified as an s sound for purpose forming plurals?

It's not about the sound itself, but rather the spelling of the word that determines whether we add an "s" or "es" to form plurals.

Here's a breakdown:

General Rule: We add "s" to most nouns to make them plural.

Exceptions:

* Nouns ending in s, x, ch, sh, or z: We add "es" to these words. Examples: buses, boxes, churches, dishes, quizzes.

* Nouns ending in a consonant + y: We change the "y" to "i" and add "es". Examples: babies, stories, cities.

* Nouns ending in a vowel + y: We simply add "s" to these words. Examples: boys, toys, keys.

Special Cases:

* Nouns ending in "o" can be tricky:

- After a consonant, we add "es": tomatoes, potatoes.

- After a vowel, we add "s": radios, studios.

- However, there are exceptions: pianos, photos, zeros, etc.

Remember: The sound at the end of a word doesn't directly determine the plural form. The spelling matters most!