-tree bbbee be-er beber beebe beete beeut beppe beppu berbe beret berre berru berte betee beter betre bett- bette beuer beure beute brebu breer breet brere brett breu- brrrr bruer bruet brute btr-t bubbe buber buret burru burte burtt burut buter butte butut ebber ebbet ebert ebure eeeee eepee epptb epure erbbe erber erept erere errtu erte erter erupt etete etree etter eturu eurre p-rep pebre peebu peere peert peete pepee peppe pept- pepup perer peret perre perte perur petbe peter petr- petre petru pette petur peure prete prute pter- ptere ptprb ptpre ptprr ptprt ptpru puber puett pupet puppe puree purer purre purte puter putre putt- putte puttu putup re-up rebbe reber rebet rebut reepe reere repet reppe reprt repub reput rere- reree reret retee reter rette reuer reuet reute rubee ruber rubup ruere ruete rupee ruper ruter rutte ruutu tbtbt tbutt teber tebet teepe teeup tepee tepet tepeu teppu teret tereu terre tert- teter tetr- tette treer treet trepp trept trere trete trett treut trubu truer trupt trute ttttt tuber tupee turbe turbt turet turre turtu turup turut tutee tutte tuuru uber- upeet upper upput upter urter urubu urupe urutu uter- utter uttur utube uturu uuuuu