Simplify the following text for a Grade 13 native English-speaking person.
Original: With the emergence of an exclusively language-based art in the 1960s , however , conceptual artists such as Joseph Kosuth , Lawrence Weiner and the English Art & Language group began a far more radical interrogation of art than was previously possible ( see below ) .
Simplified: With the emergence of an exclusively language-based art in the 1960s , however , conceptual artists began a far more radical analysis of art than was previously done .