Voiced Consonants
Your vocal cords, which are actually mucous membranes, stretch across the larynx at the back of the throat. By tightening and relaxing as you speak, the vocal cords modulate the flow of breath expelled from the lungs.
An easy way to determine whether a consonant is voiced or not is to place a finger on your throat. As you pronounce a letter, feel the vibration of your vocal cords. If you feel a vibration the consonant is a voiced one.
These are the voiced consonants: B, D, G, J, L, M, N, Ng, R, Sz, Th (as in the word "then"), V, W, Y, and Z.
But if consonants are only single letters, what are Ng, Sz, and Th? They're common sounds that are produced by blending the two consonants phonetically.
Here are some examples of words that include voiced consonants:
traveled
gloves
shells
started
changed
wheels
lived
dreams
exchanged
Voiceless Consonants
Voiceless consonants do not use the vocal cords to produce their hard, percussive sounds. Instead, they're slack, allowing air to flow freely from the lungs to the mouth, where the tongue, teeth, and lips engage to modulate the sound.
These are the voiceless consonants: Ch, F, K, P, S, Sh, T, and Th (as in "thing"). Common words using them include:
washed
coats
watched
books
seats
dropped
carts
Vowels
Vowel sounds (A, E, I, O, U) and diphthongs (combinations of two vowel sounds) are all voiced. That also includes the letter Y when pronounced like a long E.
Examples: city, pity, gritty.
Changing Voice
When consonants are put in groups, they can change the vocal quality of the consonant that follows. A great example is the past simple form of regular verbs. You can recognize these verbs because they end in "ed. " However, the consonant sound of this ending can change from voiced to voiceless, depending on the consonant or vowel that precedes it. In almost all cases, the E is silent. Here are the rules:
If the "ed" is preceded by a voiceless consonant such as K, it should be pronounced as a voiceless T. Examples: parked, barked, marked
If the "ed" is preceded by a voiced consonant sound such as B or V, it should be pronounced as a voiced D. Examples: robbed, thrived, shoved
If the "ed" is preceded by a vowel sound, it should be pronounced as a voiced D because vowels are always voiced. Examples: freed, fried, lied
Exception: If the "ed" is preceded by T, it should be pronounced a voiced "id" sound. In this case, the "e" is pronounced. Examples: dotted, rotted, plotted
This pattern can also be found with plural forms. If the consonant preceding the S is voiced, the S will be pronounced phonetically as a Z. Examples: chairs, machines, bags
If the consonant preceding the S is voiceless, then the S also will be pronounced as a voiceless consonant. Examples: bats, parks, pipes.
Connected Speech
When speaking in sentences, the ending consonant sounds can change based on the following words. This is often referred to as connected speech.
Here is an example of a change from a voiced B in the word "club" to a voiceless P because of the voiced T in "to" of the following word: "We went to the club to meet some friends. "
Here is an example of a change from a voiced D past simple verb changed to voiceless T: "We played tennis yesterday afternoon. "