Consonant voicing and devoicing

{{Short description|Phonetic sound change}}

{{Sound change}}

{{Use American English|date = February 2019}}

{{IPA notice}}

In phonology, voicing (or sonorization) is a sound change where a voiceless consonant becomes voiced due to the influence of its phonological environment; shift in the opposite direction is referred to as devoicing or surdization. Most commonly, the change is a result of sound assimilation with an adjacent sound of opposite voicing, but it can also occur word-finally or in contact with a specific vowel.

For example, the English suffix -s is pronounced {{IPA|[s]}} when it follows a voiceless phoneme (cats), and {{IPA|[z]}} when it follows a voiced phoneme (dogs).{{sfnp|Grijzenhout|2000|p=3}} This type of assimilation is called progressive, where the second consonant assimilates to the first; regressive assimilation goes in the opposite direction, as can be seen in have to {{IPA|[hæftə]}}.

==English==

English no longer has a productive process of voicing stem-final fricatives when forming noun-verb pairs or plural nouns, but there are still examples of voicing from earlier in the history of English:

• belief ({{IPA|[f]}}) – believe ({{IPA|[v]}})
• shelf ({{IPA|[f]}}) – shelve ({{IPA|[v]}})
• grief ({{IPA|[f]}}) – grieve ({{IPA|[v]}})
• life ({{IPA|[f]}}) – live ({{IPA|[v]}})
• proof ({{IPA|[f]}}) – prove ({{IPA|[v]}})
• strife ({{IPA|[f]}}) – strive ({{IPA|[v]}})
• thief ({{IPA|[f]}}) – thieve ({{IPA|[v]}})
• bath ({{IPA|[θ]}}) - bathe ({{IPA|[ð]}})
• breath ({{IPA|[θ]}}) - breathe ({{IPA|[ð]}})
• mouth ({{IPA|[θ]}}, {{abbr|n.|noun}}) – mouth ({{IPA|[ð]}}, {{abbr|vb.|verb}})
• sheath ({{IPA|[θ]}}) - sheathe ({{IPA|[ð]}})
• wreath ({{IPA|[θ]}}) - wreathe ({{IPA|[ð]}})
• advice ({{IPA|[s]}}) – advise ({{IPA|[z]}})
• house ({{IPA|[s]}}, {{abbr|n.|noun}}) – house ({{IPA|[z]}}, {{abbr|vb.|verb}})
• use ({{IPA|[s]}}, {{abbr|n.|noun}}) – use ({{IPA|[z]}}, {{abbr|vb.|verb}})

Synchronically, the assimilation at morpheme boundaries is still productive, such as in:{{sfnp|Grijzenhout|2000|p=9}}

• cat + s → cats
• dog + s → dogs ({{IPA|[ɡz]}})
• miss + ed → missed ({{IPA|[st]}})
• whizz + ed → whizzed ({{IPA|[zd]}})

The voicing alternation found in plural formation is losing ground in the modern language,{{Citation needed|date=December 2009}}. Of the alternations listed below many speakers retain only the {{IPA|[f-v]}} pattern, which is supported by the orthography. This voicing of {{IPA|/f/}} is a relic of Old English, at a time when the unvoiced consonants between voiced vowels were 'colored' by an allophonic voicing (lenition) rule {{IPA|/f/}} → {{IPA|[v]}}. As the language became more analytic and less inflectional, final vowels or syllables stopped being pronounced. For example, modern knives is a one syllable word instead of a two syllable word, with the vowel e not pronounced and no longer part of the word's structure. The voicing alternation between {{IPA|[f]}} and {{IPA|[v]}} occurs now as realizations of separate phonemes {{IPA|/f/}} and {{IPA|/v/}}. The alternation pattern is well maintained for the items listed immediately below, but its loss as a productive allophonic rule permits its abandonment for new usages of even well-established terms: while leaf~leaves in reference to 'outgrowth of plant stem' remains vigorous, the Toronto ice hockey team is uncontroversially named the Maple Leafs.

• knife – knives
• leaf – leaves
• wife – wives
• wolf – wolves

The following mutations are optional:{{Citation needed|date=December 2009}}

• bath ({{IPA|[θ]}}) - baths ({{IPA|[ð]}})
• mouth ({{IPA|[θ]}}) - mouths ({{IPA|[ð]}})
• oath ({{IPA|[θ]}}) - oaths ({{IPA|[ð]}})
• path ({{IPA|[θ]}}) - paths ({{IPA|[ð]}})
• youth ({{IPA|[θ]}}) - youths ({{IPA|[ð]}})
• house ({{IPA|[s]}}) – houses ({{IPA|[z]}})

Sonorants ({{IPA|/l r w j/}}) following aspirated fortis plosives (that is, {{IPA|/p t k/}} in the onsets of stressed syllables unless preceded by {{IPA|/s/}}) are devoiced such as in please, crack, twin, and pewter.{{sfnp|Roach|2004|p=240}}

Several varieties of English have a productive synchronic rule of /t/-voicing whereby intervocalic /t/ not followed by a stressed vowel is realized as voiced alveolar flap [ɾ], as in tutor, with the first /t/ pronounced as voiceless aspirated [tʰ] and the second as voiced [ɾ]. Voiced phoneme /d/ can also emerge as [ɾ], so that tutor and Tudor may be homophones, both with [ɾ] (the voiceless identity of word-internal /t/ in tutor is manifested in tutorial, where stress shift assures [tʰ]).