Simplify the following text for a Grade 6 native English-speaking person.
Original: The name Viá '' t Nam is a variation of `` Nam Viá '' t '' , a name that can be traced back to the Triá '' u Dynasty ( 2nd century BC ) . The word `` Viá '' t '' originated as a shortened form of BÃ ch Viá '' t , a word applied to a group of peoples then living in southern China and Vietnam .
Simplified: Viá '' t Nam ( commonly spelled Vietnam ; Viá '' tnamese for `` Southern Viá '' t '' i.e. , the nation of the Viet people in the South ) is a country in Southeast Asia .