The sounds are so far apart in the mouth that no learners will have problems with the contrast.
The only pairings with taboo words are shit/shout and tit/tout.
Interesting pairs include:
The mean density is 0.4%. The list makes 51 semantic contrast, giving a loading of 52%.
bid bowed bit bout bits bouts biz boughs cissies souses din down dinned downed dinning downing dins downs ditty doughty fill foul filled fouled filling fouling fills fouls filly foully flit flout flits flouts flitted flouted flitting flouting frizzy frowzy gill ghoul gills ghouls gill jowl gills jowls gist joust gists jousts grill growl grilled growled grilling growling grills growls grille growl grilles growls grinned ground grist groused hill howl hills howls his house hiss house ill owl ills owls it out kid cowed kill cowl killing cowling killings cowlings kills cowls knit knout knits knouts lid loud lit lout Lizzy lousy locket lockout lockets lockouts mint mount minted mounted mints mounts miss mouse missed moused misses mouses missing mousing missy mousy Ms mows myth mouth myths mouths pitch pouch pitched pouched pitches pouches pitching pouching pit pout pits pouts pitting pouting pitied pouted rid rowed shit shout shits shouts shitted shouted shitting shouting sinned sound skill scowl skilled scowled skills scowls skit scout skits scouts spit spout spits spouts spitted spouted spitting spouting sprit sprout sprits sprouts tin town tins towns tinny townee tit tout tits touts viz vows whiz wows writ rout writs routs
Credit: John Higgins