fricatives when forming noun-verb pairs or plural nouns, but there are still examples of voicing from earlier in the history of English:

* belief - believe
* shelf - shelve
* grief - grieve
* life - live
* proof - prove
* strife - strive
* thief - thieve
* bath - bathe
* breath - breathe
* mouth (, ) - mouth (, )
* sheath - sheathe
* wreath - wreathe
* advice - advise
* house (, ) - house (, )
* use (,