Here's what rhymes with lettable.
double bubble publ trouble rubble stubble redouble playable addable dirigible beatable tamable damnable friable unbridgeable attachable filtrable vocable ignitable unlikable unplayable acquirable flyable dividable uncharitable vincible unloveable imperishable imperturbable exploitable nonviable unnameable containable conformable indissoluble translatable unarguable compoundable transmutable untranslatable indemonstrable Words that almost rhyme with lettable
puddle rebuttal tuple couple subtle shuttle muddle suppl supple huddle cuddle cudgel rappel fuddle scuttle decouple befuddle uncouple oversubtle thermocouple tunnel puzzle bustle tumble buckle chuckle jumble tional juggle tussle bumble pummel duckbill tamale tousle tubful muscle humble bundle jungle funnel muzzle shovel ductile rumble rustle shuffle stumble ductal hovel hustle knuckle muffle mussel ruffle subtile fumble mumble pustule suckle caecal runnel truffle bungle guzzle nuzzle truckle gunnel gumball jugful tumbrel struggle fungal autumnal crumble bestowal grumble scuffle smuggle phrasal reshuffle snaffle snuggle trundle lungful rumple snuffle unbuckle mugful pinocle frontal triumphal colourful crustal nuptial lustful peduncle trustful crumple kerfuffle cupsful conformal carbuncle prenuptial granduncle nonvocal heptagonal prefrontal antifungal distrustful honeysuckle suboptimal mistrustful duodecimal disgruntle subcortical