The spelling of /p/ is either <p> or <pp>. The /k/ sound is spelled in many ways in this list, <c>, <k>, <ck> after short vowels, <kh> in sheikh, <qu> in toque and queue, and <ch> in ache. The last of these can give rise to spelling pronunciations.
The two sounds are fairly far apart in the mouth, but both have an unreleased allophone in syllable-final position which may be difficult to distinguish.
There are several pairs involving rude words: cop/cock, crap/crack, dip/dick, pee/key, piss/kiss, and punt/cunt.
Interesting pairs include
ape ache aped ached apes aches aping aching apse ax apses axes apt act apter actor ash-pan ash-can ash-pans ash-cans beep beak beeps beaks bleep bleak burp burke burped burked burping burking burps burkes cape cake capes cakes cheap cheek cheep cheek cheeped cheeked cheeping cheeking cheeps cheeks chip chick chips chicks chop choc chops chocs chop chock chopped chocked chopping chocking chops chocks clap clack clapped clacked clapping clacking claps clacks clip click clipped clicked clipping clicking clips clicks contraption contraction contraptions contractions cop cock cope coke coped coked coping coking copes cokes copes coax copper cocker copped cocked coppers cockers copping cocking cops cocks copses coxes Copt cocked copy cocky copyist cockiest Corp Cork corpse calks corpus caucus cr^epe crake crap crack crapped cracked crapping cracking craps cracks creep creak creeping creaking creeps creaks creepy creaky creepier creakier creepiest creakiest crop crock cropped crocked cropping crocking crops crocks crypt cricked dapper Dacca dapper Dakar deception dissection deceptions dissections deepen deacon deepens deacons dep deck depot dekko dip Dick dipper dicker dippers dickers dispose discos drape drake drapes drakes dupe duke dupes dukes flap flak flaps flax flip flick flipped flicked flipper flicker flippers flickers flipping flicking flips flicks flop flock flopped flocked flopping flocking flops flocks flops phlox fops fox gawp gawk gawps gawks grippe Greek grippes Greeks hap hack happed hacked happing hacking haps hacks harp hark harped harked harping harking harps harks hep heck hip hick hips hicks hop hock hopped hocked hopping hocking hops hocks hopes hoax inapt enact inculpate inculcate inculpated inculcated inculpates inculcates inculpating inculcating intercept intersect intercepted intersected intercepting intersecting interception intersection interceptions intersections intercepts intersects jape Jake japes jakes kip kick kipped kicked kipping kicking kips kicks knap knack knaps knacks knickers nippers lap lack lapped lacked lapping lacking laps lacks laps lax lapse lacks lapse lax leap leek leaps leeks leap leak leaped leaked leaping leaking leaps leaks lip lick lipped licked lipping licking lips licks loop Luke lop loch lops lochs lop lock lopped locked lopping locking lops locks map mac maps macs maps max mop mock mops mocks mopped mocked mopping mocking mope moke mopes mokes nap knack naps knacks nip nick nipped nicked nipping nicking nips nicks nippers knickers nipple nickel nipples nickels nips nix open oaken opt Oct overproud overcrowd P key P's keys P quay P�s quays pa car pace case paced cased paces cases pacing casing pad cad pads cads paddy caddie paddies caddies page cage paged caged pages cages paging caging pah car pail kail pain Cain pain cane pained caned paining caning pains canes pair care paired cared pairing caring pairs cares pale kail pall call palled called palling calling palls calls pall caul palls cauls pallor Calor palm calm palmed calmed palming calming palms calms palmer calmer palmers karmas palmer karma palmers karmas palmist calmest Pam cam pampas campus pamper camper pampers campers pan can panned canned panning canning pans cans panda candour pander candour pane cane panes canes pannier cannier pant cant panted canted panting canting pants cants panto canto pantos cantos pap pack paper caper papered capered papering capering papers capers par car pars cars parcel castle parcelled castled parcelling castling parcels castles pare care pared cared pares cares paring caring park carp parked carped parking carping parks carps parky khaki parley Cali Parma calmer Parma karma parr car parrs cars parry carry parried carried parries carries parrying carrying parrot carrot parrots carrots parrot carat parrots carats parrs cars parry Carrie parse cars part cart parted carted parting carting parts carts partridge cartridge partridges cartridges passed cast passed caste past cast pasts casts past caste pasts castes paste cased pastor caster pastors casters pastor castor pastors castors pat cat pats cats patch catch patches catches patching catching patchy catchy patchier catchier patchiest catchiest pate Kate patty catty Paul call Paula caller Paul caul pauper porker paupers porkers pause cause paused caused pauses causes pausing causing pause caws pause cores pause corps pave cave paved caved paves caves paving caving paw caw pawed cawed pawing cawing paws caws paw core pawed cored paws cores paw corps paws corps pawed chord pawed cord pawl call pawls calls pawl caul pawls cauls pawn corn pawned corned pawning corning pawns corns paws cause pay K pays K's pay Kay pea key peas keys pea quay peas quays peal keel pealed keeled pealing keeling peals keels pear care pears cares pearl curl pearled curled pearling curling pearls curls pearly curly pearlier curlier pearliest curliest pease keys pease quays pecked kept pee key peed keyed peeing keying pees keys pee quay pees quays peel keel peeled keeled peeling keeling peels keels peep peak peeped peaked peeping peaking peeps peaks peg keg pegs kegs pelt Celt pelts Celts pen ken penned kenned penning kenning pens kens Penny Kenny pep peck pepped pecked pepping pecking peps pecks pepper pecker peppers peckers peppery peccary peptic pectic per cur perk kirk perks kirks permission commission permit commit permits commits permitted committed permitting committing permute commute permuted commuted permutes commutes permuting commuting perry Kerry pert curt pertly curtly pertness curtness petal kettle petals kettles pew Q pews Q's pew cue pews cues pew queue pews queues pewter cuter pill kill pills kills pillar killer pillars killers pin kin pine kine pined kind ping king pings kings pink kink pinked kinked pinking kinking pinks kinks pip pick pipped picked pipping picking pips picks pipe pike pipes pikes pipette piquet piss kiss pissed kissed pisses kisses pissing kissing pit kit pits kits pitted kitted pitting kitting pitch kitsch pith kith pity kitty pitied kitted pities kitties plaid clad plan clan plans clans plank clank planked clanked planking clanking planks clanks plaque clerk plaques clerks plash clash plashed clashed plashes clashes plashing clashing platter clatter platters clatters play clay pleat cleat pleats cleats pliant client plod clod plods clods plop clock plopped clocked plopping clocking plops clocks plot clot plots clots plotted clotted plotting clotting ploughed cloud ploy cloy ploys cloys pluck cluck plucked clucked plucking clucking plucks clucks plump clump plumped clumped plumping clumping plumps clumps plunk clunk plunks clunks poach coach poached coached poaches coaches poaching coaching pocks cocks pocks cox pocked cocked pod cod podded codded podding codding pods cods poke coke poked coked pokes cokes poking coking polar cola pole coal poled coaled poles coals pole kohl poll coal polled coaled polling coaling polls coals poll col polls cols poll kohl pollard collared polled cold polling-station coaling-station polling-stations coaling-stations Polly collie poly collie polys collies pond conned pone cone pones cones pony coney ponies coneys pooh coo pooh coup pool cool pooled cooled pooling cooling pools cools poop coop poops coops pop cop popped copped popping copping pops cops pop pock popped pocked pops pocks Pope coke Popes cokes Popes coax poppa copper poppas coppers poppet pocket poppets pockets poppy copy poppies copies populate copulate populated copulated populates copulates populating copulating population copulation populations copulations pore caw pored cawed pores caws pore core pored cored poring coring pores cores pore corps pores corps pores cause pored chord pored cord pork cork porn corn porous chorus porpoise corpus porpoises corpuses port caught port court ported courted porting courting ports courts portion caution portioned cautioned portioning cautioning portions cautions portly courtly poses cosies posh cosh poshed coshed poshes coshes poshing coshing posset cosset possets cossets post coast posted coasted posting coasting posts coasts postal coastal poster coaster posters coasters posy cosy posies cosies pot cot pots cots pottage cottage pottages cottages potter cottar potters cottars pouch couch pouched couched pouches couches pouching couching pour caw poured cawed pours caws pour core poured cored pouring coring pours cores pour corps pours corps poured chord poured cord pours cause power cower powered cowered powering cowering powers cowers powered coward praise craze praised crazed praises crazes pram cram prams crams prank crank pranks cranks prate crate prated crated prates crates prating crating prays craze preacher creature preachers creatures Pres Cres press cress pressed crest preys craze priced Christ prick crick pricking cricking pricks cricks pride cried priest creased prime crime primed crimed primes crimes priming criming primp crimp primped crimped primping crimping primps crimps prior crier priors criers prise cries pristine Christine prize cries pro crow prone crone prop crop propped cropped propping cropping props crops proper cropper props prox pro crow pros crows prose crows prosier crozier proud crowd Pru crew prude crewed prude crude prune croon prunes croons pruned crooned pruning crooning pruners crooners pry cry prying crying pries cries pried cried pub cub pubs cubs pubic cubic pud could puddle cuddle puddled cuddled puddles cuddles puddling cuddling puff cuff puffed cuffed puffing cuffing puffs cuffs pukka cuppa punning cunning punt cunt punts cunts pup puck pups pucks pur_ee cur_e pur_ees cur_es pure cure purl curl purled curled purling curling purls curls purlieus curlews purr cur purrs curs purred curd purse curse pursed cursed purses curses pursing cursing pus cuss putt cut putts cuts putter cutter putters cutters putting cutting quip quick rap rack rapped racked rapping racking raps racks rap wrack rape rake raped raked rapes rakes raping raking rapt racked reap reek reaped reeked reaping reeking reaps reeks reap wreak reaped wreaked reaping wreaking reaps wreaks relapse relax relapsed relaxed relapses relaxes relapsing relaxing rep wreck reps wrecks reps Rex rip rick ripped ricked ripping ricking rips ricks ripe Reich sap sac saps sacs sap sack sapped sacked sapping sacking saps sacks saps sax sceptre sector sceptres sectors sculpt skulked seep seek seeping seeking seeps seeks seep Sikh seeps Sikhs Sept sect shape shake shapes shakes shaping shaking shape sheikh shapes sheikhs sharp shark sharps sharks sheep chic shop shock shopped shocked shopper shocker shoppers shockers shopping shocking shops shocks sip sic sip sick sipped sicked sipping sicking sips sicks sips six slap slack slapped slacked slapping slacking slaps slacks sleep sleek sleeping sleeking sleeps sleeks sleeper sleeker slip slick slips slicks slipper slicker slippers slickers snap snack snaps snacks snip snick snipped snicked snipping snicking snips snicks snoop snook snoops snooks snooper snooker snoopers snookers soap soak soaped soaked soaping soaking soaps soaks sop Soc sop sock sopped socked sopping socking sops socks spa scar spas scars Spain skein span scan spanned scanned spanning scanning spans scans spanner scanner spanners scanners spar scar sparred scarred sparring scarring spars scars spare scare spared scared spares scares sparing scaring spat scat spate skate spates skates spatter scatter spattered scattered spattering scattering spatters scatters spawn scorn spawned scorned spawning scorning spawns scorns speed ski'd spew skew spill skill spilled skilled spills skills spin skin spinning skinning spins skins spinney skinny spirt skirt spirted skirted spirting skirting spirts skirts spit skit spits skits spittle skittle spool school spools schools spore score spores scores spot Scot spots Scots spouse scows spout scout spouted scouted spouting scouting spouts scouts sprawl scrawl sprawled scrawled sprawling scrawling sprawls scrawls spree scree sprees screes spud scud spuds scuds spunk skunk spy sky spied skied spies skies spying skying stop stock stopped stocked stops stocks stopping stocking stoppings stockings stripe strike stripes strikes stripped strict sup suck supped sucked supping sucking sups sucks supper succour suppers succours supper sucker suppers suckers supple suckle tap tack tapped tacked tapping tacking taps tacks tape take tapes takes taping taking taper taker tapers takers tapir taker tapirs takers tapped tact taps tax tip tic tips tics tip tick tipped ticked tipping ticking tips ticks tippet ticket tippets tickets tipple tickle tippled tickled tippler tickler tipplers ticklers tipples tickles tippling tickling tope toque topes toques torpor talker torpors talkers trap track trapped tracked trapper tracker trappers trackers trapping tracking traps tracks trapped tract trip trick tripped tricked tripping tricking trips tricks triple trickle tripled trickled triples trickles tripling trickling tup tuck tups tucks turps Turks type tike types tikes warp walk warped walked warping walking warps walks weep weak weep week weeps weeks whelp whelk whelps whelks whip wick whips wicks whippet wicket whippets wickets whisper whisker whispered whiskered whispers whiskers wisp whisk wisps whisks wispy whiskey wrap rack wrapped racked wrapping racking wraps racks wrap wrack yap yak yaps yaks
Credit: John Higgins