▁V ow els ▁L ule ▁S á mi ▁poss esses ▁the ▁following ▁v ow els : ▁▁▁ ▁can ▁be ▁real ised ▁as ▁a ▁true ▁di ph th ong , ▁or ▁a ▁long ▁mon op ht ong ▁. ▁ ▁Long ▁ ▁and ▁the ▁di ph th ongs ▁ ▁and ▁ ▁occur ▁only ▁in ▁str essed ▁sy ll ables . ▁ ▁Long ▁ ▁and ▁ ▁are ▁very ▁rare , ▁as ▁is ▁short ▁. ▁They ▁also ▁only ▁occur ▁in ▁str essed ▁sy ll ables . ▁ ▁Short ▁ ▁and ▁long ▁ ▁can ▁occur ▁in ▁un str essed ▁sy ll ables , ▁but ▁only ▁when ▁a ▁preceding ▁str essed ▁sy ll able ▁contains ▁. ▁ ▁Cons on ant ▁length ▁and ▁grad ation ▁ ▁Cons on ants , ▁including ▁clusters , ▁that ▁occur ▁after ▁a ▁str essed ▁sy ll able ▁can ▁occur ▁in ▁multiple ▁distinct ive ▁length ▁types , ▁or ▁quantities . ▁These ▁are ▁convention ally ▁label led ▁quantity ▁ 1 , ▁ 2 ▁and ▁ 3 ▁or ▁Q 1 , ▁Q 2 ▁and ▁Q 3 ▁for ▁short . ▁The ▁con son ants ▁of ▁a ▁word ▁alternate ▁in ▁a ▁process ▁known ▁as ▁con son ant ▁grad ation , ▁where ▁con son ants ▁appear ▁in ▁different ▁quantities ▁depending ▁on ▁the ▁specific ▁gram mat ical ▁form . ▁Norm ally , ▁one ▁of ▁the ▁possibilities ▁is ▁named ▁the ▁strong ▁grade , ▁while ▁the ▁other ▁is ▁named ▁weak ▁grade . ▁The ▁con son ants ▁of ▁a ▁weak ▁grade ▁are ▁normally ▁quantity ▁ 1 ▁or ▁ 2 , ▁while ▁the ▁con son ants