The /u/ vowel is usually spelled <oo>, <ew>, <u>, <o> after <wh> in who'll and who's, and occurs in the letter name U. The /eɪ/ diphthong is spelled in a number of ways including <aCe>, <ay>, <ei>, <ai> in waif, and occurs in the letter names A, J and K.
This is a contrast between a long vowel and a diphthong, well separated in the mouth and distinguished by lip-rounding. It is not a problem for any group of learners.
There is one taboo word pair: coon/cane.
Interesting pairs include:
allude allayed
cachou cachet
delude delayed
footle fatal
revolution revelation
toucan taken
The density figure is 5.9%. The set makes 145 semantic contrasts giving a loading of 51.8%.
ablution oblation ablutions oblations allude allayed bloom blame bloomed blamed blooming blaming blooms blames blued blade blues blaze boo bay boos bays booed bayed booing baying boo bey boos beys boob babe boobs babes booby baby boobies babies boon bane boost based boosted basted boosting basting boosts bastes boot bait booted baited booting baiting boots baits boot bate boots bates booted bated booting bating booth bathe booths bathes booze bays booze beys brew brae brews braes brew bray brew brayed brewing braying brews brays brewed braid brood brayed brood braid brooded braided brooding braiding broods braids Bruce brace bruise brays bruised braised bruises braises bruising braising buhl bail cachou cachet cachous cachets clew clay coo K coos K's cool kail coon cane coons canes coop cape coops capes cooper caper coopers capers coot Kate crews craze croon crane crooned craned crooning craning croons cranes croup crêpe cruise craze cruised crazed cruises crazes delude delayed do day do's days doom dame dooms dames drew dray droop drape drooped draped drooping draping droops drapes flew flay flue flay flues flays fluke flake flukes flakes flume flame flumes flames food fade foods fades fool fail fooled failed fooling failing fools fails footle fatal Frome frame fruit freight fruited freighted fruiting freighting fruits freights ghoul Gael ghouls Gaels ghoul gale ghouls gales glued glade glues glaze gnu nay gnu née gnu neigh gnus neighs goo gay Goole Gael goon gain goons gains grew gray groove grave grooves graves groover graver groovy gravy group grape groups grapes Hoo hay hoot hate hooted hated hooting hating hoots hatres Hoovering Havering Jew J Jews J's joule gaol joules gaols June Jane lieu lay loo lay loos lays loom lame loomed lamed looming laming looms lames loon lain loons lanes loose lace loosed laced looses laces loosing lacing loot late looter later loser laser losers lasers lose laze loses lazes losing lazing Lucy lacy Luke lake moo May mood made mood maid moods maids moon main moons mains moo may moos Mays moose mace mooses maces moot mate mooted mated mooting mating moots mates new nay new née new neigh news neighs ooze A's pooh pay pool pail pooled paled pooling paling pools pails Pru pray prude prayed revolution revelation revolutions revelations rood raid roods raids roost raced root rate rooted rated rooting rating roots rates route rate routes rates routed rated routing rating rude raid ruder raider rue ray rues rays rule rail ruled railed rules rails ruling railing rulings railings rune rain runes rains ruse rays school scale schooled scaled schooling scaling schools scales scoot skate scooted skated scooting skating scoots skates scooter skater scooters skaters shoes chaise shooed shade Sioux say slew slay slewing slaying slews slays slew sleigh slewed sleighed slewing sleighing slews sleighs snook snake snooks snakes soon sane sooner saner soonest sanest spook spake spoon Spain stooge stage stooged staged stooges stages stooging staging stool stale stools stales strew stray strewed strayed strewing straying strews strays strewn strain suit sate suited sated suits sates suiting sating swoon swain swoons swains tomb tame tombs tames tool tail tooled tailed tooling tailing tools tails toucan taken trews trays Troon train troops traipse truce trace truces traces true tray U yea U's yeas who'll hail who's haze woo way woos ways woo weigh wooed weighed wooing weighing woos weighs wooed wade woof waif woofs waifs wound waned
John Higgins, Shaftesbury, December 2009