Translation of tontería

Robert wants to tell us not only about nature and its secrets but also about the ability of the human being to recognize what happens around us. We see only the nice side if we just read and do not analyze.
The place I have been to is famous for its many language schools. People come from all over the world to learn Spanish and practise their language skills. I guess there are more than two hundred schools there.
About multiple translations: We want students to memorize 'idioma' and 'lengua' as they are both very common. The best we could do is to place them in 2 different lessons, so that users learn them both.