Simplify the following text for a Grade 8 native English-speaking person.
Original: Alex Dimitri Song Billong ( born 9 September 1987 ) , more commonly known as Alex Song , is a Cameroonian footballer who plays for English Premier League side Arsenal and the Cameroon national team as a midfielder .
Simplified: Alex Song ( born 9 September 1987 ) is a Cameroonian football player . He plays for Arsenal and Cameroon national team .