efeler effere effete efreet efter- eleele elekte ellett errett feeler fekete felker feller felter feltre ferfel ferfer ferrel ferrer ferret fertee fertek ferter fetter fettle fleete fleker flekke fletre freele frefre frekel frelte fretel frette fterer fterre k-tree keefer keeffe keeker keekle keeler keffel kelkel kellee keller kelter kereft kerker kertee ketler ketter kettle kleeer kleket krefft krekel kreker kretek leelee leerer leetle leffel lefter lekker lerret letter lettre r-tree re-let reefer reeffe reeker reeler refeel refeet refeff refell refelt refert refete reflee reflet refret refter releef releke reller rereel reteer reteet retell retere retree retret rettel retter t-tree teetee teeter telefe telele telete telfer tellee teller terete terkel terrel terrer terret terter tertre tetele tetete tetter treete trefet trefle trefte treker tretee trette