Simplify the following text for a Grade 10 native English-speaking person.
Original: Isla Culebra ( , `` Snake Island '' ) is an island-municipality of Puerto Rico originally called Isla Pasaje and Isla de San Ildefonso .
Simplified: Isla Culebra ( Snake Island ) is an island-municipality of Puerto Rico originally called Isla Pasaje and Isla de San Ildefonso .