Simplify the following text for a Grade 11 native English-speaking person.
Original: They have participated in several activities for promoting Leonese language , as Leonese language Day in 2008 or the Mother Language Day in 2009 , where they signed a communicate with the Leonese language associations for promoting this language .
Simplified: Also they develop some activities for promoting Leonese language between the population , as the Leonese language Day , in all the provinces of the Kingdom of LeÃ n.