Finnish, Swedish, English, German and Spanish. I understand Norwegian and Danish (and speak a little bit of both), and a little bit of Estonian and Hungarian.
And I think I can still read some Middle Egyptian.
How do you stay fluent in so many languages? 
When you come from a language that is only spoken by a few, then you have to know other languages, if you want to experience anything outside the borders of your own country.
Don't know how it is in Sweden, but in the Netherlands hardly any program on TV is dubbed. So, you'll hear foreign languages almost any day you switch on the TV. Music, most of the songs are in another language. And, in school foreign languages are obligatory. It's not that you are the only one having knowledge of another language, most people do. So, there are things available in other languages too.
The non spoken languages are the hardest to keep up with for me. Then the language I hear the least. For me, that is French. But, with a kid going to secondary school, my French is getting a boost again, even when I don't help her with her school assignments for French at all.
My French never was good. My German sucked in school, but, meeting German people, and mutual visiting did a lot of good for my German. I do still mess up with the gender of words, but, for understanding what I am hearing or reading that doesn't matter. Can make me being understood right a bit hard sometimes.
