Focus on the pronunciation of challenge
English definition of “challenge”
/ˈtʃæl·əndʒ/ n [C/U] (EXPRESSION OF DOUBT)
› a questioning or expression of doubt about the truth or purpose of something, or the right of a person to have or do something: [U] Because of the way this research was done, its findings are open to challenge. [C] The president is clearly anticipating a new challenge to his authority.