Simplify the following text for a Grade 6 native English-speaking person.
Original: DenÃ lson de Oliveira AraÃ jo ( born 24 August 1977 in Diadema ) , commonly known as DenÃ lson , is a Brazilian retired footballer , who was last contracted at AO Kavala .
Simplified: DenÃ lson de Oliveira AraÃ jo ( born 24 August 1977 ) is a Brazilian football player .