Pronunciation of final -s

[diana de las casas]

What are the rules in regards to pronunciation of the final s in plural and 3rd person singular present? When does one use s, z, and iz? Thanks for your help.

[mykwyner]

We use the "z" sound when the word ends in a voiced sound.

sofa...sofaz
job...jobz
food...foodz
bee...beez etc.

We use the "s" sound when the word ends in an unvoiced sound.

tic...tics
fluff...fluffs
pop...pops
cat...cats

We use the "ez" sound when the word ends in ch, sh, s, x, z and maybe another I can't think of.

church...churchez
wish...wishez
dress...dressez
box...boxez
buzz...buzzez

Note: The Zs above are for pronunciation. We never spell the words like that.

[Casiopea]

Additionally, most students memorize "voiced" and "unvoiced sounds" but there's an easier way to figure out when to use the sounds [s], [z], and [Iz].

Place two fingers over your throat, where your larnyx is located, say the word "sofa", and notice if the last sound "a" produced vibration where your fingers are. If there's vibration, then use [z]:

sofa => sofa[z], spelled "sofas"

If there isn't vibration, use [s]:

sleep => sleep[s], spelled "sleeps"

Here are two examples for you to try:

tab ([z] or [s]?)
tap ([z] or [s]?)

Now, if a word ends in a sound that sounds like [s] or [z], then use [Iz] (spelled "-es"). For example,

church+[Iz]
bush+[Iz]
fox+[Iz]
cause+[Iz]