The /k/ sound is spelled with <c> or <k> initially, and <ck>, <ch> or <ke> medially or finally. Two exceptional spellings are <qu> in pique and <ch> in Reich, though many English speakers will use a fricative in the latter. The /z/ sound is normally spelled <z> initially and <se> or <zz> medially or finally, but note the exceptional <ts> in Tsar. A great many of the /z/ sounds in this list are plurals or 3rd-person inflections of words ending in vowels.
The contrast is between a voiceless velar stop and a voiced alveolar fricative. It causes no problems.
Interesting pairs include:
buttock butters
hammock hammers
peruke peruse
recourse resource
Suffolk suffers
Taboo word pairs include: fuck/fuzz and wank/whangs.
The mean density value is 1.3%. The list makes 208 semantic distinctions, a loading of 79%.
ache A's alike allies antic antes arc R's auk awes bake baize bake bays balk boars balk bores bank bangs bannock banners bark baas basic basses beak B's belike belies bike buys bike byes bilk bills bloke blows boutique bootees brake braes brake braise braking braising break brays break braes break braise breaking braising break brays brink brings buck buzz bucking buzzing bucked buzzed bunk bungs burke burrs buttock butters cake K's calk cause calking causing calked caused Cannock cannas cap zap capped zapped capping zapping caps zaps car Tsar cars Tsars chalk chaws chalk chores cheek cheese chicle chisel choke chose civic civvies clank clangs clink clings cloak close cloaking closing cloaked closed colic collies cone zone coned zoned cones zones coning zoning coo zoo coos zoos cork cause corking causing corked caused crake craze croak crows debark debars Dec Des dickeys dizzies Dicky dizzy dike dies dike dyes drake drays duck does duke dues eke E's eke ease eking easing eked eased elk L's enc N's fake phase faking phasing faked phased fickle fizzle flake flays fluke flues folk foes fork fours freak frees freak freeze freaking freezing fuck fuzz Gallic galleys gawk gauze gawky gauzy gawkier gauzier gawkiest gauziest Gorky gauzy hack has hake haze hammock hammers hank hangs hawk haws hawker hawser hawkers hawsers hick his hike hies hike highs hulk hulls ilk ills irk errs jack jazz jacking jazzing Jackie jazzy Jake J's jerky Jersey Ken Zen Kenneth zenith key zee king zing kink kings kink zinc kip zip kipped zipped kipping zipping kips zips kipper zipper kippers zippers kirk curs knuckle nuzzle knuckled nuzzled knuckles nuzzles knuckling nuzzling lacquer lazar lacquers lazars lake lays lake laze like lies link lings logic lodges lucre loser mark mars make Mays maker maser makers masers mattock matters meekly measly Mick Ms mickle mizzle milk mills moke mows mucky muzzy muckier muzzier muckiest muzziest muckle muzzle music muses oak O's oak owes park parrs park parse parking parsing parked parsed peak P's peak peas perk purrs peruke peruse physic fizzes pike pies pink pings pique P's pique peas pocket posit pocketed posited pocketing positing pockets posits poke pose poking posing poked posed poker poser pokers posers poky posy politic polities pork pause pork paws psychic psyches puke pews quick quiz quickies quizzes rake raise raking raising rakes raised rake rays recourse resource Reich rise rink rings sec says seek C's seek seize seeking seizing seeker Caesar shark shahs sickle sizzle sickles sizzles Sikh C's Sikh seize silk sills sink sings skulk sculls slake slays slink slings sneak sneeze sneaking sneezing sneaked sneezed snook snooze soak sews soak sows spake spays spark spars spike spies squawk squaws squeak squeeze squeaking squeezing squeaked squeezed squeaker squeezer squeakers squeezers stake stays stalk stores stark stars steak stays stink stings stoke stows stork stores Suffolk suffers talk tawse talkies tawses tank tangs teak T's teak teas teak tease think things tike ties toque toes Vic viz wake ways wake weighs walk wars wank whangs weak wees week wheeze week wees weak wheeze whelk wells wick whiz wink wings woke woes work whirrs wreck res York yaws
John Higgins, Shaftesbury, May 2010.