bo-bo bobr bogor bogu bogur bombo boomb booru borbo borgo borgu bormo boro- borom boroo borou borro borum bourg brmmm brobo brom- bromo broom brrrr brugg brumm bugoo bumbo bumbu burgo burgu buroo burro burru go-go go-oo gobbo gogro gombo gomor gomur goobo gorgo grgur grogg gromo groom grrrr grubb grumo gubbo gubru gumbo gummb gummo guroo gurro gurum gurur mbogo mboro mburu mmmmm mobor mobro mombo mombu moogo mooro morbo mormo moror morou morro morum mrmom mrorr mugur mumbo mummu murgo murom muror murro murru murum o-r-b oboro obrom ogogo ogugu omoro ooooo orbom ormur orobo oromo orrgo orrum oruro ouoro ro-ro robbo robo- robor robur roomu rorbu roumm rubor rumbo rummo rummu rumor ruomu ubobo ugro- ugrug umbro umour uroob urour urubu uuuuu