▁the ▁accus ative ▁second - person ▁pl ural ▁pron oun ▁i u ▁ ▁> ▁northern ▁jou ▁ ▁versus ▁southern ▁u ▁. ▁ ▁Old ▁Dutch ▁, ▁, ▁ ▁merge ▁into ▁a ▁central ising ▁di ph th ong ▁, ▁sp elled ▁. ▁ ▁Like wise , ▁Old ▁Dutch ▁ ▁( from ▁Pro to - G erman ic ▁) ▁becomes ▁a ▁central ising ▁di ph th ong ▁, ▁sp elled ▁ ▁or ▁. ▁ ▁Ph on em isation ▁of ▁um la ut ▁for ▁back ▁v ow els , ▁resulting ▁in ▁a ▁new ▁ph on eme ▁ ▁( from ▁earlier ▁Old ▁Dutch ▁ ▁before ▁ ▁or ▁). ▁Un like ▁most ▁other ▁German ic ▁languages , ▁um la ut ▁was ▁only ▁ph on em ic ised ▁for ▁short ▁v ow els ▁in ▁all ▁but ▁the ▁eastern most ▁areas ; ▁long ▁v ow els ▁and ▁di ph th ongs ▁are ▁una ffect ed . ▁ ▁Vo ic eless ▁fr ic atives ▁become ▁vo iced ▁sy ll able - initial ly : ▁ ▁> ▁, ▁ ▁> ▁ ▁( mer ging ▁with ▁ ▁from ▁Pro to - G erman ic ▁), ▁ ▁> ▁. ▁( 1 0 th ▁or ▁ 1 1 th ▁century ) ▁ ▁V ocal ▁reduction : ▁V ow els ▁in ▁un str essed ▁sy ll ables ▁are ▁weak ened ▁and ▁merge ▁into ▁, ▁sp elled ▁. ▁( 1 1 th ▁or ▁ 1 2 th ▁century ) ▁Long ▁v ow els ▁seem ▁to ▁have ▁remained ▁as ▁such , ▁at ▁least ▁ ▁is ▁known ▁to ▁have ▁remained