The distinction between the articulatory use of voice and the phonological use rests on the distinction between
phone (represented between square brackets) and
phoneme (represented between slashes). The difference is best illustrated by a rough example. The English word
nods is made up of a sequence of phonemes, represented symbolically as , or the sequence of , , , and . Each symbol is an abstract representation of a phoneme. That awareness is an inherent part of speakers' mental grammar that allows them to recognise words. However, phonemes are not sounds in themselves. Rather, phonemes are, in a sense, converted to phones before being spoken. The phoneme, for instance, can actually be pronounced as either the phone or the phone since is frequently devoiced, even in fluent speech, especially at the end of an utterance. The sequence of phones for
nods might be transcribed as or , depending on the presence or strength of this devoicing. While the phone has articulatory voicing, the phone does not have it. What complicates the matter is that for English, consonant phonemes are classified as either voiced or voiceless even though it is not the primary distinctive feature between them. Still, the classification is used as a stand-in for phonological processes, such as vowel lengthening that occurs before voiced consonants but not before unvoiced consonants or vowel quality changes (the sound of the vowel) in some dialects of English that occur before unvoiced but not voiced consonants. Such processes allow English speakers to continue to perceive difference between voiced and voiceless consonants when the devoicing of the former would otherwise make them sound identical to the latter. English has four pairs of
fricative phonemes that can be divided into a table by
place of articulation and voicing. The voiced fricatives can readily be felt to have voicing throughout the duration of the phone especially when they occur between vowels. However, in the class of consonants called
stops, such as , the contrast is more complicated for English. The "voiced" sounds do not typically feature articulatory voicing throughout the sound. The difference between the unvoiced stop phonemes and the voiced stop phonemes is not just a matter of whether articulatory voicing is present or not. Rather, it includes
when voicing starts (if at all), the presence of
aspiration (airflow burst following the release of the closure) and the duration of the closure and aspiration. English voiceless stops are generally
aspirated at the beginning of a stressed syllable, and in the same context, their voiced counterparts are voiced only partway through. In more narrow
phonetic transcription, the voiced symbols are maybe used only to represent the presence of articulatory voicing, and aspiration is represented with a superscript
h. When the consonants come at the end of a syllable, however, what distinguishes them is quite different. Voiceless phonemes are typically unaspirated,
glottalized and the closure itself may not even be released, making it sometimes difficult to hear the difference between, for example,
light and
like. However, auditory cues remain to distinguish between voiced and voiceless sounds, such as what has been described above, like the length of the preceding vowel. Other English sounds, the vowels and sonorants, are normally fully voiced. However, they may be devoiced in certain positions, especially after aspirated consonants, as in
coffee,
tree, and
play in which the voicing is delayed to the extent of missing the sonorant or vowel altogether. ==Degrees of voicing==