Simplify the following text for a Grade 11 native English-speaking person.
Original: The U.S. Music Publishers ' Association ( MPA ) , which represents sheet music companies , launched a legal campaign against such websites in December 2005 , the MPA 's president , Lauren Keiser , said the free lyrics web sites are `` completely illegal '' and wanted some website operators jailed .
Simplified: The United States Music Publishers ' Association ( MPA ) , which represents sheet music companies , created a campaign against such sites in December 2005 . MPA president Lauren Keiser said that the sites are `` completely illegal '' and that he wanted to see some site operators put in prison .