▁tone : ▁the ▁pitch ▁of ▁the ▁voice ▁first ▁dro ps ▁from ▁a ▁mid - level ▁to ▁the ▁bottom ▁of ▁the ▁speaker ’ s ▁range ▁of ▁pitch ▁and ▁then ▁r ises ▁back ▁to ▁mid . ▁In ▁Northern ▁Vietnam , ▁it ▁is ▁pron ounced ▁with ▁the ▁cre ak y ▁rising ▁tone : ▁the ▁pitch ▁of ▁the ▁voice ▁r ises ▁from ▁mid - level ▁to ▁the ▁top ▁of ▁the ▁speaker ’ s ▁range ▁of ▁pitch , ▁but ▁with ▁con str icted ▁vocal ▁c ords , ▁a kin ▁to ▁a ▁gl ott al ▁stop ▁in ▁the ▁middle ▁of ▁the ▁v owel . ▁See ▁Vietnam ese ▁t ones . ▁ ▁The ▁pron unci ation ▁of ▁N gu y ễ n , ▁English ▁speak ers ▁pron ounce ▁as ▁ ▁or ▁. ▁ ▁Ch anges ▁of ▁family ▁name ▁There ▁have ▁been ▁various ▁points ▁in ▁Vietnam ' s ▁history ▁at ▁which ▁people ▁have ▁changed ▁their ▁family ▁name ▁to ▁" N gu y ễ n ." ▁When ▁the ▁L ý ▁D ynast y ▁fell ▁in ▁ 1 2 3 2 , ▁Tr ầ n ▁Th ủ ▁ Đ ộ , ▁who ▁orch estr ated ▁the ▁over throw ▁of ▁it , ▁forced ▁L ý ' s ▁descend ants ▁adopted ▁the ▁name ▁due ▁to ▁the ▁naming ▁tab oo ▁of ▁Tr ầ n ▁L ý , ▁grand father ▁to ▁em peror ▁Tr ầ n ▁C ả n h . ▁ ▁During ▁ 1 0 0 0 ▁years , ▁from ▁ 4 5 7 ▁to ▁H ồ ▁Qu ý ▁Ly , ▁in ▁H ả i ▁D