The /f/ sound is spelled with <f>, <ff>, <gh> in laugh or <ph> in aphid. The /ʤ/ sound is spelled <j>, <g(e)> or <dg(e)>.
The contrast is between a voiceless labio-dental fricative and a voiced alveolar affricate. It is not a problem.
Interesting pairs include:
ferny journey
firkin jerkin
fossil jostle
offenders agendas
traffic tragic
The mean density value is 3.1%. The list makes 107 semantic distinctions, a loading of 55%.
afar ajar aphid aged buff budge buffing budging buffed budged caff cadge chaff charge chaffing charging coffer codger coffers codgers defect deject defected dejected defecting dejecting defects dejects defection dejection doff dodge doffing dodging effect eject effected ejected effecting ejecting effects ejects effing edging F edge fab jab fact jacked fade jade faded jaded fades jades fag jag fagged jagged fagging jagging fags jags fail gaol failed gaoled failing gaoling fails gaols fain Jane fake Jake fakes jakes fan Jan far jar farrow Jarrow faugh jaw fear jeer feared jeered fearing jeering fears jeers fee G fees G's feign Jane fell gel felled gelled felling gelling fells gels fem gem fen gen fens gens fend genned fender gender fenders genders ferny journey ferry jerry ferries jerries fester jester festers jesters fetid jetted fey J fib jib fibbed jibbed fibbing jibbing fibs jibs fibber gibber fibbers gibbers fig jig figs jigs figure jigger figured jiggered figures jiggers files Giles fill Jill fill gill fills gills fin djinn finns djinns fin gin finns gins Finn djinn Finns djinns Finn gin Finns gins firkin jerkin firkins jerkins firm germ firms germs fist gist fists gists fitters jitters five jive fives jives fob job fobbed jobbed fobbing jobbing fobs jobs foe Jo fog jog fogged jogged fogging jogging fogs jogs foist joist foists joists folk joke folks jokes folly jolly follies jollies fool jewel fools jewels fool joule fools joules ford jawed for jaw fore jaw Forfar forger forge George fosse joss fosses josses fossil jostle fossils jostles foul jowl fouls jowls foully jowly four jaw fours jaws Fowey Joy fowl jowl fowls jowls fudge judge fudges judges fug jug fugs jugs fumble jumble fumbled jumbled fumbles jumbles fumbling jumbling function junction functions junctions funk junk funks junks funky junkie fussed just gruff grudge infect inject infected injected infecting injecting infects injects infection injection infections injections infest ingest infested ingested infesting ingesting infests ingests kaffir cadger kaffirs cadgers laugh large leaf liege maffick magic murphies merges offender agenda offenders agendas phase J's Phil Gill phone Joan phoney Joanie phut jut puffy pudgy puffier pudgier puffiest pudgiest ref Reg refection rejection refections rejections riff ridge safe sage safely sagely scurf scourge serf serge serf surge slough sludge surf serve surf surge surfing surging surfed surged traffic tragic wafer wager wafers wagers waif wage