MICROSTOMOUS

is it mi mm mo mu oi om or os si so ti to um us ut

cis coo cor cos cot cru cum cur cut ism its mic mim mir mis moc mom moo mor mos mot mum mus mut oms oot orc ors ort our out rim roc rom rot rum rut sic sim sir sis sit som sos sot sou sri sum tic tis tom too tor tui umm uts

cist coir coos coot corm cors coss cost cots cris crit crus curs curt cuss cuts isms mics mirs miso miss mist mocs momi moms moor moos moot mors mort moss most mots mums muss must muts omit oots orcs orts otic ours oust outs rims riot rocs roms room root roti roto rots rout rums rust ruts scot scum scut sics sims sirs sits smit smut soms soot sori sort sots sour sous sris stir stum suit sumo sums tics tiro toms toom torc tori toro tors toss tour trim trio tuis uric