The /s/ sound is spelled with <s>, <ss> or <ce>. The /z/ sound is spelled with <s>, <se> or <z>. Seventeen of the pairs are homographs arising from using voicing to turn a noun into a verb as in abuse/abuse. Other common patterns are pairings with an -ous adjective ending and an -ers agent-noun plural such as solicitous/solicitors, and an -ess feminine suffix paired with an -ies abstract noun plural, such as sorceress/sorceries.
This is a contrast between two sibilants distinguished only by voicing. It is a known source of difficulty for Scandinavian, Dutch and German learners, and may cause problems elsewhere.
Taboo word pairs include arse/R's.
Some questions arise about syllable counts. How minimal are the pairs pious/pyres or sharpness/sharpeners, both of which were identified by the algrithm?
The mean density value is 1.2%. The list makes 207 semantic distinctions, a loading of 74%.
abase obeys abuse abuse abuses abuses ace A's adduce adieus adulteress adulteries adulterous adulterers adventurous adventurers advice advise Alice alleys ancestress ancestries Angus angers apiece appease arse R's ass as averse avers baas baas base baize basis basses berths berths bias buyers bodice bodies bonus boners bourse boors brace braes brace braise braces braises bracing braising braced braised brace brays brass bras Bruce brews bus buzz buses buzzes busing buzzing bused buzzed C zee campus campers case K's caucus corkers cease C's cease seize ceasing seizing ceased seized ceases seizes cellars zealous census censers cirrus sirrahs close close closes closes closer closeer coarse cause complacence complaisance complacent complaisant coppice copies countess counties course cause courses causes coursing causing coursed caused coyness coiners curse curs cutlass cutlers dace days dance darns decease disease deceases diseases deceased diseased decrease decrees dense dens deuce dues device devise devices Devizes dice dies diffuse diffuse dose does dose doze doses dozes dosing dozing dosed dozed douse dhows douse dowse dousing dowsing doused dowsed douses dowses duchess duchies dunce duns else L's Erse errs excuse excuse excuses excuses face phase faces phases facing phasing faced phased false falls fence fens fierce fears fleece fleas force fours foundress foundries fuss fuzz fussy fuzzy fussier fuzzier fussiest fuzziest gorse gauze grace grays grace graze graces grazes gracing grazing graced grazed gristle grizzle gross grows Guinness guineas hearse hers heiress aeries hence hens hiss his hoarse haws hoarsely Horsley hoarser hawser horse haws house house humus humours ice eyes idolatress idolatries induce endues Joyce joys juice Jews Kansas cancers lace lays lace laze laces lazes lacing lazing laced lazed lacy lazy lacier lazier laciest laziest lance larns laundress laundries lease leas less Les lice lies loose loos loose lose looses loses loosing losing looser loser mace Mays mace maze maces mazes mace maize manse mans minus miners Miss Ms missal mizzle missals mizzles misuse misuse misuses misuses moose moos Morse maws mouse mows murderous murderers muscle muzzle muscled muzzled muscles muzzles muscling muzzling nebulous nebulas Nice knees niece knees noose gnus Norse gnaws once ones onus owners pace pays pampas pampers Paris parries parlous parlours pass parse passes parses passing parsing passed parsed peace P's peace peas penance pennons pence pens Phyllis fillies piece P's piece peas pierce peers pinnace pinnies pious pyres place plays porpoise paupers posset posit possets posits precedent president precedents presidents precious pressures press Pres price pries price prise prices prises pricing prising priced prised price prize prices prizes pricing prizing priced prized primers primus prioress priories prospectus prospectors puce pews purse purrs quince quins race raise races raises racing raising raced raised race rays race raze races razes racing razing raced razed racer raiser racers raisers rice rise riotous rioters said Z sap zap sapped zapped sapping zapping saps zaps sauce saws sauce sores scarce scares science scions scion Zion sconce scones sea zee see zee sense sends sharpness sharpeners sing zing sink zinc sip zip sipped zipped sipping zipping sips zips slanderous slanderers sluice slews slumberous slumberers solicitous solicitors sorceress sorceries sou zoo sous zoos souse sows sown zone space spays sparse spars spice spies stiffness stiffeners sue zoo sues zoos Swiss swiz tense tens tenuous tenures terrace terrors trace trays treatise treaties trice tries truce trews use use used used uses uses vice vies victorious victorias Wallace wallahs waltz walls whence wens worse whirrs
John Higgins, Shaftesbury, November 2010.