Simplify the following text for a Grade 11 native English-speaking person.
Original: Mu isamaa , mu Ã nn ja rÃ Ã m ( `` My Fatherland , My Happiness and Joy '' ) was adopted as the national anthem of the Republic of Estonia in 1920 , and again in 1990 .
Simplified: `` Mu isamaa , mu Ã nn ja rÃ Ã m '' ( `` My Fatherland , My Happiness and Joy '' in English ) is the official national anthem of Estonia .