Simplify the following text for a Grade 7 native English-speaking person.
Original: Grabowski was the leader of the Warsaw Esperanto Society and the Polish Esperanto society for a long time . In 1908 , he became the director of the Grammar Section of the Esperanto Academy .
Simplified: In the years 1908 -- 1914 Grabowski was in charge of the first Esperanto courses for a few schools in Warsaw .