Finnish class

I finally went to visit the Finnish class that they are having in the Faculty of Arts. I wanted to ask them if they'd want to meet up and practise Finnish with me, and I'd practise Portuguese. The students were very shy, but it's so cute to hear someone foreigner speaking Finnish. We talked a bit and then they practised a bit of grammar, and I found out that Finnish is ridiculously difficult. They were learning consonantal gradation (astevaihtelu). E.g. katto -> katolla. Where does the other t disappear? rikas -> rikkaalla. The s just changed into t? They must be a bit insane to be learning Finnish. Or desperately in love with Ville Valo.