The /v/ sound is spelled with <v> or <ve>, while the /ʧ/ sound is spelled <ch>, <tch> or <tu> in feature.
The contrast is between a voiced labio-dental fricative and a voiceless alveolar affricate. It is not a problem for any learners.
Interesting pairs include:
fever feature
river richer
vulva vulture
The mean density value is 1.8%. The list makes 46 semantic distinctions, a loading of 61%.
breve breach cove coach Denver denture divvies ditches dove Dutch Eve each ever etcher fever feature fevered featured fevers features have hatch having hatching lav latch leave leach leaving leaching miniver miniature move mooch moving mooching moved mooched movies mooches Nov notch peeve peach peeving peaching peeved peached reeve reach rev retch revving retching rev wretch river richer rove roach serve search serving searching served searched server searcher servers searchers starve starch starving starching starved starched vain chain vamp champ vamped champed vamping champing vamps champs vane chain vanes chains vary chary vase chars vat chat vats chats veer cheer veered cheered veering cheering veers cheers vein chain veined chained veins chains very cherry vest chest vests chests vex Czechs vex checks vex cheques vied chide vine chine vine chaine vines chines vivid chivied voice choice voices choices vow chow vows chows vox chocks V's cheese vulva vulture vulvas vultures
John Higgins, Shaftesbury, November 2010.