Voice (phonetic)

Most consonants in English can be paired off into two sounds whose only substantive difference is whether they are spoken with vibration of the vocal cords or not. All vowels are voiced, spoken with vibrating vocal cords. This may sound intimidating if you haven't studied phonetics - but take heart. There is an easier way. Most people can detect whether they are vibrating their vocal cords, using one of three methods.

Some people, often those who have trained as singers, just know it - and they are usually right. The second and third methods are slightly harder, but simple for lay-people. Either: place your fingertips on your larynx ('Adam's apple') while you say the sounds. In this case, you should be able to feel the vibration, particularly if you speak the consonants in pairs. Alternatively: close your ears by pressing your fingers across the entrance. In this case, you should be able to hear the differences. Voiced sounds vibrate; unvoiced (or voiceless) sounds don't vibrate.

One warning: all vowels are voiced. So when we say the names of letters, we often make a short unvoiced sound, but follow it with a longer voiced sound, as in 'tee' and 'kay', where the initial consonant is unvoiced, but the following vowel is fully voiced.

The relevant pairings for you to investigate the phenomenon of voicing are: first, the stop consonants (those in which the flow of air through the mouth is cut off), with the unvoiced one of the pair first, in each instance). These are: p and b (both bilabial consonants, or sounds made with both lips); t and d (alveolars, made with the tooth-ridge behind the upper teeth); and k and g (velar consonants, made on the hard palate, or roof of the mouth). Then come the continuants, consonants in which the air flow is modified but not cut off. These are: f and v (labio-dentals, made with (upper) lips and (lower) teeth); /T/ and /D/ (dentals, or interdentals, made with the tongue and both sets of teeth); s and z (also alveolars, like t and d - but continuant); and /ʃ/ (usually spelled 'sh') and /ʒ/ (as in vision) (palatals, made on the soft palate, at the front of the roof of the mouth).

All three of the nasal consonants (made by directing the stream of air through the nose) are voiced. These are m, n and /ŋ/, the sound of 'ng' in words like 'sing'.

Sounds that are made by a stop followed by a continuant are known as affricates. The English affricates are shown by the IPA symbols /tʃ/, for the unvoiced version and /dʒ/ for the voiced.