The /3/ vowel is spelled with <er>, <ir>, <ear>, <ur>, <our> in journey and <or> in worst. The /eɪ/ vowel is spelled <aCe>, <ai> or <ay>, and is seen in the letter names A and K.
This is a contrast between a long vowel and a diphthong. The starting positions are fairly close but it does not seem to be a problem for learners.
The nature/nurture pair features in much current scientific debate on genetics, while the words surf and safe turn up in various slogans about guarding against internet porn. Other interesting pairs include:
bursar baser
certain Satan
earthiest atheist
fervour favour
merger major
purple papal
surfaced safest
The density figure is 6.94%. The set makes 112 semantic contrasts giving a loading of 52.3%.
Bert bait bird bayed blurred blade blurs blaze burble babel burbles babels burke bake burked baked burkes bakes burking baking burly Bailey burn bane burr bay burrs bays burr bey burrs beys bursar baser burst based bursting basting bursts bastes cert sate certs sates certain Satan churn chain churned chained churning chaining churns chains curl kail curs K's curse case cursed cased curses cases cursing casing curt Kate curve cave curved caved curves caves curving caving derv Dave dirtied dated double-first double-faced earl ail earls ails earthiest atheist err A errs A's erred aid Erse ace fern fain fern feign ferns feigns fervour favour firm fame firmed famed firs phase first faced furl fail furled failed furling failing furls fails germs James girl Gael girls Gaels girl gale girls gales girt gait hers haze hertz hates hurl hail hurled hailed hurling hailing hurls hails hurt hate hurting hating hurts hates hurtful hateful inert innate irk ache irked ached irking aching irks aches jerk Jake jerks jakes journey Janie kirk cake kirks cakes learn lain learn lane learns lanes lurk lake lurks lakes mercies maces merger major mergers majors murk make nerve knave nerves knaves nervy navy nurture nature nurtures natures pearl pail pearls pails pearl pale pearled paled pearling paling pearls pales pert pate purge page purged paged purges pages purging paging purple papal purposes papacies purr pay purred paid purrs pays purse pace pursed paced purses paces pursing pacing quirk quake quirks quakes return retain returned retained returning retaining returns retains serf safe serfs safes serge sage serve save served saved serves saves serving saving servings savings server saver servers savers shirk shake shirking shaking shirks shakes shirker shaker shirkers shakers skirl scale skirls scales skirt skate skirted skated skirting skating skirts skates slur slay slurs slays slur sleigh slurred sleighed slurs sleighs spirt spate spirts spates spur spay spurred spayed spurs spays spurn Spain spurred spade stern stain sterns stains Stirling staling stir stay stirred stayed stirs stays stirred staid surfaced safest surge sage surges sages term tame termed tamed terming taming terms tames timeserving timesaving Turk take Turks takes turps tapes ugh A unfurling unfailing urge age urged aged urges ages urging ageing urgency agency urgent agent were way were weigh wert wait whirl wail whirled wailed whirling wailing whirls wails whirls Wales whirr way whirrs ways whirr weigh whirrs weighs whirred wade word wade worded waded wording wading words wades word weighed work wake worked waked working waking works wakes worst waist worsts waists worst waste worsted wasted worsting wasting worsts wastes years yeas
John Higgins, Shaftesbury, December 2009