The spelling of /p/ is always <p> and the /w/ semivowel is <w>, <wh>, <u> in suede and occurs initially in the exceptional words one and ones. Note that the contrast only occurs initially or within initial clusters.
The contrast is between a voiceless plosive and a semivowel. Both sounds are bilabial so there is a slight chance of mishearing in fluent speech. There is little risk of this being a systematic problem for any learner.
Interesting pairs include:
pillow willow
policy Wallasey
ponder wander
pottage wattage
spindle swindle
The mean density value is 4.5%. The list makes 226 semantic distinctions, a loading of 52%.
P we P wee P's wees P's wheeze paced waist paced waste pack whack packed whacked packing whacking packs whacks packer whacker packers whackers packs wax pact whacked page wage paged waged pages wages paging waging paid wade paid weighed pail wail pails wails pail whale pails whales pails Wales pain wain pains wains pain wane pained waned paining waning pains wanes pain Wayne pair ware pairs wares pair wear pairing wearing pairs wears pair where pairs where's pale wail paled wailed paling wailing pales wails pale whale paled whaled pales whales paling whaling paler whaler pales Wales pall wall palled walled palling walling palls walls palter Walter pane wain panes wains pane wane panes wanes pane Wayne pang whang pangs whangs pare ware pares wares pare wear pares wears paring wearing pare where pares where's paste waist pastes waists paste waste pasted wasted pastes wastes pasting wasting pate wait pates waits pate weight pates weights Paul wall pause wars pave waive paved waived paves waives paving waiving pave wave paved waved paves waves paving waving paw war pawed warred paws wars paw wore pawed ward pawl wall pawls walls pawn warn pawned warned pawning warning pawns warns pawn worn pax wax paxes waxes pax whacks pay way pays ways pay weigh paying weighing pays weighs pay whey pea we pea wee peas wees peak weak peak week peaks weeks peal weal peals weals peal we'll peal wheel pealing wheeling pealed wheeled peals wheels pealed weald pealed wield pear ware pears wares pear wear pears wears pear where pears where's pearl whirl pearled whirled pearling whirling pearls whirls pearl whorl pearled whorled pearls whorls pearled world peas wheeze pease wees pease wheeze peat wheat pee we peed we'd pee wee peeing weeing pees wees peed weed peek weak peek week peeks weeks peel weal peels weals peel we'll peel wheel peeled wheeled peeling wheeling peels wheels peeled weald peeled wield peer Wear peer weir peers weirs peer we're peered weird pees wheeze peeve we've peeve weave peeves weaves peeving weaving peeves weaves peke weak peke week pekes weeks pelt welt pelts welts pen wen pens wens pen when pens when's pence whence pending wending penned wend pepped wept per were per whirr peri weary peris wearies perk work perked worked perking working perks works perm worm permed wormed perming worming perms worms perry wherry pert wert Perth worth pest west pet wet pets wets petted wetted petting wetting pet whet pets whets petted whetted petting whetting Pete wheat pi Y pis Y's pi why pis whys pis wise pick wick picks wicks picker wicker picket wicket pickets wickets pie why pies whys pie Y pies Y's pied wide pier Wear pier weir piers weirs pier we're pies wise pig Whig pigs Whigs pig wig pigged wigged pigging wigging pigs wigs pigeon widgeon pigeons widgeons pile while piled whiled piles whiles piling whiling pile wile piles wiles piled wild pill will pills wills pillow willow pillows willows pimple wimple pimples wimples pin whin pins whins pin win pinning winning pins wins pinch winch pinched winched pinches winches pinching winching pine whine pined whined pines whines pining whining pine wine pined wined pines wines pined wind ping wing pinged winged pinging winging pings wings pink wink pinked winked pinking winking pinks winks pinned wind pinny whinny pinnies whinnies pinny Winnie pipe wipe piped wiped pipes wipes piping wiping piper wiper pipers wipers pip whip pipped whipped pipping whipping pips whips pique weak pique week piques weeks pissed whist pit whit pits whits pit wit pits wits pitch which pitch witch pitches witches pitching witching pith withe pity witty pod wad podded wadded podding wadding pods wads poke woke policy Wallasey polled wold Polly Wally poly Wally pond wand ponds wands ponder wander pondered wandered pondering wandering ponders wanders poof woof poofs woofs pooh woo pop whop popped whopped popping whopping pops whops poppa whopper poppas whoppers pore war pored warred pores wars poring warring pore wore pored ward pork walk porker walker porkers walkers porn warn porn worn port wart ports warts porter water porters waters pose woes posh wash posher washer pot watt pots watts pot what pots what's pot wot pottage wattage pottages wattages pouffe woof pouffes woofs pound wound pour war poured warred pouring warring pours wars pour wore poured ward pud wood pud would pudden wooden pull wool pulls wools pulley woolly pulleys woolies pun one puns ones pun won purl whirl purled whirled purling whirling purls whirls purl whorl purled whorled purls whorls purled world purr were purr whirr purred whirred purring whirring purrs whirrs purred word purse worse pursed worst Pyle while Pyle wile pyorrhoea wirier pyre wire pyres wires pyx wicks spade suede spade swayed Spain swain spam swam spank swank spanked swanked spanking swanking spanks swanks spare swear spares swears sparing swearing spawn sworn spay sway spayed swayed spaying swaying spays sways spayed suede speed Swede speeds Swedes spell swell spelled swelled spells swells spelling swelling spellings swellings spill swill spilled swilled spilling swilling spills swills spindle swindle spindles swindles spine swine spoon swoon spooned swooned spooning swooning spoons swoons spore swore spot swat spots swats spotted swatted spotting swatting