The spelling of /k/ is <c> or <k>. The /j/ sound is spelled <y>, and it also occurs in the letter name U. The contrast can only occur initially.
This is a contrast between a voiceless stop and a voiced semivowel. It causes no problems.
Interesting pairs include:
The figure for the mean density is 0.6%. The set makes 36 semantic contrasts, a loading of 54%.
call yawl calls yawls Calne yarn cam yam cams yams cap yap capped yapped capping yapping caps yaps card yard cards yards cause yaws caw yaw cawed yawed cawing yawing caws yaws caw your caws yours chord yawed coax yokes cob yob cobs yobs coke yoke coked yoked coking yoking cokes yokes con yon coo ewe coos ewes coo U coos U's coo you cool you'll cool Yule cord yawed core yaw cored yawed cores yaws core yore core your cores yours Cork York corn yawn corned yawned corning yawning corns yawns cot yacht cots yachts cowl yowl cowling yowling cowls yowls cur year curs years curling yearling curly yearly K yea K's yeas Kate Yate kelp yelp ken yen kenned yenned kenning yenning kens yens key ye khan yarn khans yarns quay ye
John Higgins, Shaftesbury, August 2010.