When you are speaking English it is important to recognize the difference between voiced sounds and voiceless sounds.

A voiced sound is a sound that causes your vocal chords to vibrate. A voiceless sound does not cause your vocal chords to vibrate.

American English has 8 voiced consonant sounds and 16 voiceless consonant sounds. All of the vowel sounds (about 14) are voiced.

Try this so you can see what I mean.

Put your fingers lightly on your throat and say "zoo". You should feel a vibration when you say the /z/. Keep your fingers on your throat and say "Sue". You should not feel a vibration when you say the /s/.

The /z/ is voiced and the /s/ is voiceless.

One reason why it is important to know the difference between voiced and voiceless sounds is because the letter "s" at the end of a word can have a voiced sound /z/, /ez/ or a voiceless sound /s/.

Plurals, possessives and third person singular verbs all end in "s" and the "s" can have three different sounds-
/s/ a voiceless sound
/z/ a voiced sound
/ez/ a voiced sound

When a word ends in a voiceless consonant the added "s" is pronounced /s/.

Here is an example: map/s/ - since the /p/ in the word maps is a voiceless sound, the "s" ending is also voiceless.

If a word ends in a voiced sound the "s" ending is also voiced.

Here is an example: love/z/-since the /v/ in the word loves is voiced, the "s" ending is also voiced and sounds like /z/.

Words that end in the three sibilant sounds take the voiced /ez/ plural ending.
/sh/ pushes
/tch/ watches
/dgz/ judges

This /ez/ sound adds a syllable to the word.

It is important to pronounce voiced and voiceless sounds correctly if you want to improve your American accent. Saying these sounds incorrectly will contribute to your foreign accent.

Susan Ryan is an American English pronunciation and accent reduction teacher in Washington, D.C. Visit her website at Accent Reduction Classroom to read more articles like this and to find out about her online courses that will help you improve your American accent http://accentreductionclassroom.com/.