Simplify the following text for a Grade 8 native English-speaking person.
Original: He worked as a speechwriter for the conservative-liberal People 's Party for Freedom and Democracy ( VVD ) , and later served as parliamentary assistant to party leader Frits Bolkestein from 1990 to 1998 .
Simplified: He began working as an assistant ( helper ) for Frits Bolkestein in 1990 . In September 2004 , he left People 's Party for Freedom and Democracy ( VVD in Dutch , the language spoken in the Netherlands ) .