Vowel /ɪ/ is generally spelled <i> or <y>. The /əʊ/ diphthong turns up in numerous different spellings including <o>, <oe>, <oa>, <ow>, <oCe> and in French loan words <eau> and <ot> (pierrot).
These two sounds are far enough apart for the contrast to cause no problems, although individually the two sounds are among the trickiest for learners to produce.
Taboo word pairings are pissed/post, tits/totes and willie/willow.
Interesting pairs include:
commission commotion
ditty dhoti
ditty ditto
ellipse elopes
grotty grotto
monarchy Monaco
pittances potencies
tittle total
Although the mean density is 1.9%, this conceals a very high density (17.8%) from the diphthong side. The list makes 214 semantic contrasts, giving a loading of 56%.
abbey Abo abbeys Abos Ali aloe alley aloe alleys aloes bandy bandeau bandies bandeaux Barry barrow belly bellow bellied bellowed bellies bellows bellying bellowing Bernie Brno bestrid bestrode Bicester boaster bid bode bidding boding bids bodes bill bole bills boles billed bold billy billow billies billows bin bone bins bones bit boat bits boats bitter boater bitters boaters biz beaux built bolt breeches broaches brick broke brig brogue brigs brogues builder bolder builders boulders Cali Carlow chick choke chicks chokes click cloak clicked cloaked clicking cloaking clicks cloaks commission commotion commissions commotions convict convoked crick croak cricked croaked cricking croaking cricks croaks Crosby crossbow dill dole dim dome dimmed domed dims domes dinner donor dinners donors dint don't dip dope dipped doped dipping doping dips dopes ditty dhoti ditties dhotis ditty ditto dizzies dozes djinn Joan doggie doggo dominie domino dominies dominoes drill droll ellipse elopes emission emotion emissions emotions evict evoked fairy Pharaoh fairies Pharaohs fickle focal fill foal filled foaled filling foaling fills foals fin phone finned phoned fins phones Finn phone Finns phones fix folks fizz foes flit float flits floats flitted floated flitting floating folly follow follies follows frizz froze galleys gallows gild gold gill goal gills goals gillie goalie gillies goalies gin Joan glib globe grin groan grinned groaned grinning groaning grins groans grip grope gripped groped gripping groping grips gropes grist grossed grit groat grits groats grotty grotto gusty gusto Halle hallow harry harrow harried harrowed harries harrows harrying harrowing hicks hoax hid hoed hill hole hills holes hilly holy hillier holier hilliest holiest him home hip hope hips hopes hippie hippo hippies hippos his hoes hissed host holly hollow homey homo hymn home hymning homing hymned homed hymns homes id ode idiom odium if oaf in own inner owner inning owning inn own inns owns intermezzi intermezzo is O's it oat its oats jib job jibs jobs jilt jolt jilted jolted jilting jolting jilts jolts Judy judo kick coke kicked coked kicking coking kicks coax kid code kidded coded kidding coding kids codes kill coal killed coaled killing coaling kills coals killers colas kilt colt kilts colts kin Colne kip cope kipped coped kipping coping kips copes kissed coast kit coat kits coats kitted coated kitting coating knit note knitted noted knitting noting Kobe kobo Lib lobe lid lode lid load lidded loaded lids loads lift loafed Lily lowly lip lope lipped loped lips lopes lives loaves Liz lows limb loam limn loam Lymm loam maestri maestro Mali Marlow marry marrow marries marrows Mick moke mid mode middle modal mill mole mills moles milled mould miller molar millers molars milt moult missed most mist most mission motion missions motions mitt moat mitts moats mix mokes monarchy Monaco Ms mows nibble noble nibbles nobles nil knoll nip nope nit note nits notes obi oboe obis oboes oozy ouzo paces pesos panty panto panties pantos peaky pekoe peri pierrot peris pierrots pick poke picked poked picking poking picks pokes picker poker pickers pokers pill pole pills poles pillar polar pillow polo pinny pony pinnies ponies pin pone pins pones pip Pope pips Popes pissed post pistil postal pitch poach pitched poached pitches poaches pitching poaching pitcher poacher pitchers poachers pittances potencies quit quote quits quotes quitted quoted quitting quoting quitters quotas remit remote rib robe ribbed robed ribbing robing ribs robes rich roach riches roaches rid road rids roads rig rogue rigs rogues rill r�le rills r�les rim Rome rim roam rimmed roamed rimming roaming rims roams rip rope ripped roped ripping roping rips ropes river rover rivers rovers sally sallow sallied sallowed sallies sallows sallying sallowing shilling shoaling shin shewn sic soak sick soak sicked soaked sicking soaking sicks soaks Sid sewed sill sole sills soles sill soul sills souls sillies solos silly solely sip soap sipped soaped sipping soaping sips soaps skilled scold skip scope slid slowed slip slope slipped sloped slipping sloping slips slopes solely solo sorry sorrow spick spoke stick stoke sticked stoked sticker stoker stickers stokers sticking stoking sticks stokes still stole stills stoles strict stroked tally tallow tarry taro tic toque tick togue ticks toques tilde told till toll tills tolls Tim tome tin tone tinned toned tinning toning tins tones tinny Tony tip tope tipped toped tipping toping tips topes tit tote tits totes tittle total trill troll trilled trolled trilling trolling trills trolls trip trope trips tropes truces trousseaus verses versos Wally wallow whinny winnow whinnied winnowed whinnies winnows whinnying winnowing whiz woes wick woke willed wold willie willow willies willows windy window wrist roast wrists roasts writ rote