The contrast is probably not a great source of difficulty for learners.
There is one unexpected pair due to -r occurring in an inflected form though silent in the root, keyring and caring. Other interesting pairs include:
cheese chairs
deed dared
impede impaired
sneeze snares
squeeze squares
The mean density is 3.5%. The 144 pairs make 95 contrasts, giving a semantic loading figure of 66%.
B bare B's bares B bear B's bears be bare be bear bead bared bean bairn beans bairns bee bare bees bares bee bear bees bears been bairn bleed blared cheese chairs deed dared D dare D's dares deed dared E air E's airs E Ayr E e'er E ere E heir E's heirs ease airs ease heirs fee fair fees fairs fee fare feed fared fees fares flea flair fleas flairs flea flare fleas flares flee flair flees flairs flee flare flees flares glee glare glees glares he hair he hare he Herr heed hared impede impaired keen cairn keens cairns key care keyed cared keys cares keyless careless keyring caring knee ne'er lea lair leas lairs lead laird leads lairds lee lair lees lairs Leeds lairds Leigh lair me mare me mayor mi mare mi mayor P pair P's pairs P pare P's pares P pear P's pears pea pair peas pairs pea pare peas pares pea pear peas pears pease pairs pease pares pease pears pee pair peed paired pees pairs pee pare peed pared pees pares pee pear pees pears quay care quays cares re rare she share ski scare ski'd scared skis scares sneeze snares speed spared squeeze squares steed stared T tare T's tares T tear T's tears tea tare teas tares tea tear teas tears tease tares tease tears tee tare tees tares tee tear tees tears thee their thee there thee they're these theirs these there's ti tare ti tear we ware we'd wared we wear we where wee ware weed wared wees wares wee wear wees wears wee where wees where's wheeze wares wheeze wears wheeze where's ye yeahGeographical: Outside English-speaking countries, most visitors are from Venezuela, Hong Kong, Saudi Arabia, Yemen, Vietnam, Spain, Jordan, Turkey, German, South Korea, Mexico, France, Ecuador, Malaysia and India. Average 15 visitors per month.
John Higgins, Shaftesbury, January 2011.