Simplify the following text for a Grade 7 native English-speaking person.
Original: The Yaqui River ( RÃ o Yaqui in Spanish ) ( Hiak Vatwe in Yaqui ) is a river in the state of Sonora in northwestern Mexico .
Simplified: The Yaqui River ( RÃ o Yaqui in Spanish ) ( Hiak Vatwe in Yaqui ) is a river in the state of Sonora in northwest Mexico .