Simplify the following text for a Grade 8 native English-speaking person.
Original: On 4 April 1959 , French Sudan was joined with Senegal to form the Mali Federation , which became fully independent within the French Community on 20 June 1960 .
Simplified: On April 4 , 1959 , French Sudan was joined with Senegal to form the Mali Federation . This became fully independent but still inside the French Community on June 20 , 1960 .