Voiced vs. unvoiced sounds
How can you make two different sounds when your tongue is in the same position in your mouth for both of them?
There are quite a few consonants (known as "paired consonant sounds") that are pronounced this way. One letter in the pair is called a "voiced sound," and the other is called an "unvoiced sound."
When you pronounce a voiced sound, you use your vocal chords to make the sound (if you put your fingers on your throat you will feel your vocal chords vibrate.) When you make an unvoiced sound you use only the front of your mouth, and all you will feel is a short explosion of air coming out of your mouth.
The following list identifies pairs of words that use either voiced or unvoiced sounds, and I've added the International Phonetic Alphabet (IPA) transcription to help you understand these sounds, as well as a diagram your mouth as you pronounce these words.
Voiced Unvoiced
B book (bʊk) P please (pliz)
V vanilla (vəˈnɪlə) F five (faɪv)
TH they (ðeɪ) TH thirty (ˈθɜrdi)
D dish (dɪʃ) T ten (tɛn)
Z zero (ˈzɪroʊ) S sir (sɜr)
J jump (ʤʌmp) CH chair (ʧɛr)
G good (gʊd) K king (kɪŋ)
Additional resources:
You can use http://lingorado.com/ipa/ to listen to these--and other--words, as well as to get their IPA transcriptions. You can also use it to discover the difference between British and American pronunciations.
