Voice (phonetics)

Voice

Voice, or voicing, is an important idea in the study of speech sounds, known as phonetics and phonology. It helps us understand the difference between some sounds we make when we talk. Speech sounds can be either voiced or voiceless.

Voicing describes what happens when the vocal folds in our throats vibrate as we make a sound. For example, the sounds we make with the English letters "s" and "z" are different because of voicing. If you put your fingers on the place where your Adam's apple is, you can feel a vibration when you say "z" but not when you say "s." This vibration is what makes a sound voiced.

In many European languages, vowels and some consonants like "m," "n," "l," and "r" are usually voiced. However, some languages only use voiced sounds and do not have any voiceless consonants. Understanding voicing helps people study how we make and understand speech sounds.

Notation

The International Phonetic Alphabet uses special letters to show the difference between voiced and voiceless sounds, like [p b] and [t d]. There is also a symbol called a diacritic, ⟨◌̬⟩, that can be added to letters to show voicing.

Unicode includes these symbols.

In English

The English word nods is made up of a sequence of sounds called phonemes, shown as /nɒdz/. These symbols represent ideas in our minds that help us recognize words. But when we say these words, the sounds can change a little.

For example, the /z/ sound in nods can be said as either the [s] sound or the [z] sound, depending on how we say it. Sometimes, the [z] sound has vibration in our throats, but the [s] sound does not.

English classifies certain consonant sounds as either voiced or voiceless, even though this isn’t the main way they differ. This classification helps us notice differences.

In English, sounds like /f/ and /z/ can be either voiced or voiceless. But for sounds like /p, t, k, b, d, ɡ/, the difference is more about when the vibration starts and how we release the sound. Vowels and other smooth sounds are usually fully voiced, but they can become voiceless in some positions.

Degrees of voicing

There are two ways to think about voicing in a sound: how strong it is and how long it lasts. Sometimes a sound is called "half voiced" or "partially voiced." This can mean the sound is quiet or that the voicing only happens for part of the sound. In English, it usually means the voicing happens only for part of the sound.

Some languages, like Juǀʼhoan, have special sounds where the voicing starts but then stops partway through. These sounds can still have extra air or strong bursts of air even though they start with voicing. Examples include sounds like [b͡pʰ, d͡tʰ, d͡tsʰ, d͡tʃʰ, ɡ͡kʰ] and [d͡tsʼ, d͡tʃʼ], as well as some click sounds. The language Lun Bawang also has these kinds of sounds, along with regular voiced and voiceless sounds like /p, b, b͡p/.

Voice and tenseness

Some languages have two sets of sounds that seem similar but are made differently. For example, in some Alemannic German dialects, there are pairs like /p t k f s x …/ and /b d ɡ v z ɣ …/. These sounds feel different, but they do not use voice—our voice boxes do not vibrate to make them. Instead, the difference is because of tenseness. One sound is tighter (called fortis) and the other is looser (called lenis).

Scientists think this tight-loose difference might be related to voiced and voiceless sounds. They believe how we hear and make these sounds might share a common feature, connecting voice, tenseness, and even sound length.