In this section we will try to clarify the difference between the voiced consonants and the unvoiced consonants.

If you want to master English pronunciation you have to able to distinguish between these two types of consonants. This is necessary for you to learn the proper pronunciation when you learn new vocabulary. And more importantly you need to know the difference between voiced and unvoiced consonants to be able to pronounce the words of English correctly. What makes one consonant be voiced and another not?

A consonant is voiced when it makes the vocal cords vibrate. It is voiceless when it is pronounced without vibrating the vocal cords.

The sound of the letters "p" and "b"

For example, the sounds indicated by the letters "b" and "p" differ only in their vocalization (voicing). The are both "bilabials", that is, they are produced by closing both lips. But the "b" is voiced and the "p" is unvoiced. In this article, we will follow common practice and indicate the letters of the alphabet with quotes (“b” and “p”) and the sounds with slashes (/b/ and /p/)

You can appreciate the difference by lightly touching with the tips of your fingers your "Adam's Apple" (the voice box that you can see in the front of your throat) as you pronounce the word bowl . You can feel the vibration with the tips of our fingers. Concentrate on the first sound, the consonant /b/ before passing to the vowel represented by the "o". Notice that you can lengthen the sound (something is heard!) without the "o". This is because /b/ is a voiced consonant.

Now pronounce the word pole. Do you feel the vibration in the vocal cords? No. The reason is that /p/ is an unvoiced consonant. Notice that you you can't lengthen the sound or hear anything.

When you pronounce these sounds, don't forget the advice we already gave you in other articles: exaggerate the value of the vowel "o" with a strong English accent!

Listen to the following exercise until you can distinguish betwen the two sounds and produce them yourself.

You should be able to telll the difference between the /p/ and the /b/ in the sentence The doctor said: "Bill, take your pill!

Try it now!

The sounds of the English letters /k/ (sometimes "c") and /g/

It is not only the sounds /p/ and /b/ that are voiced or unvoiced. The same distinction holds for the sounds represented by the letters "k" y "g" in the International Phonetic Alphabet. By the way, do you see that it will not be hard for you to learn the symbols of the IPA? Many of the symbols, like the k and the g are already familiar to you. They are the normal letters of the alphabet.

The IPA symbol k interests us now. It is the "hard" sound of the letter "c", the sound that the letter "c" usually takes before the letters "a", "o", and "u", for example in the words car, coat, cube.

Now can you see how the IPA system makes it easy for you to learn the pronunciation of new words? Now, we don't have to worry that sometimes the letter "c" has the sound of the IPA symbol k (as in the word cold) or that sometimes the same letter "c" of the English alphabet is pronounced as the IPA s (as in the words cell ).
!
Now try to feel in your voice box the vibration in the word coal! You can't because it is the unvoiced partner in the pair. If you touch your voice box while you pronounce the word goal, you do feel the vibration because the sound g is voiced.

Practice the two words coal and goal. But keep on pronouncing the the English vowel with its lengthening. Exaggerate the English language character of the vowel. Don't pronounce it as if it were col or gol in your language. And also remember the explosive nature of the consonant represented by the "c" in English when it is pronounced as the IPA k. Blow out the candle when you say coal.

Pero… ¡Qué no suene como si hablaras de repollo (la col en el Perú) o del fútbol (el gol)!
¡Cuidado con tu acento hispano!

Did you notice that we review various important things about the English sounds as we move along in this book. From now on, in your listening and in your practice, you must remember the explosive consonants, the special English vowels, and the voiced or unvoiced consonants.

Listen and practice all these essential elements of English pronunciation.

The sound of the letters "t" and "d"

Consider the pair of words tear and dear. Do the same with these words as you did above with the pairs of words coal and goal, and pole and bowl. Can you distinguish which of the initial sounds is voiced and which is unvoiced? Both are pronounced in almost the same place in the mouth but the initial sound of these two words is different in that the letter "t" is usually voiceless and the "d" is usually voiced. However, do NOT think that the letter "d" in English is always voiced. You will see that sometimes this letter "d" represents a voiceless sound. This is a VERY important lesson in the pronunciation of English and when you learn how and when the "d" is unvoiced it will be a valuable tool for you in your mastery of English.

This difference between the letters "d" and "t" in English is very important in the matter of the past tense of verbs. We will treat this elsewhere.

Also there is another pair of voiced and unvoiced consonants, the sounds represented in English by the letters "s" and "z". We will study them in their most important contexts, that of the third person singular of the present of verbs, and that of the plural of nouns.

But for now, concentrate on the consonants we just looked at.
Now listen and practice! Listen wherever you can (or listen in our book) to the different pairs of voiced and unvoiced consonants. Then make them yourself.

P and B
K and G
T and D

This lesson is taken from the book, “Word Power” which contains sound files that let you hear the vowels and consonants and practice their pronunciation.