Translation:In Finland, one speaks Finnish and Swedish.
For those confused about the word order in this statement: In a sentence that begins with location or time ex: "I dag" or "I bergen" the subject comes after the verb. It's raining a lot today. "I dag regner det mye." The subject "det" (it) gets put after the verb "regner" (rains/raining)
The majority of native speakers of each language are located in certain parts of the country, but Finnish speaking Finns are all taught Swedish at school. Swedish speakers do not commonly learn Finnish at school. Whether a Finnish speaking Finn is fluent in Swedish is a different matter, though, and depends on their personal interest in the language.
This Wikipedia article might be able to answer your question: https://en.wikipedia.org/wiki/Swedish-speaking_population_of_Finland
The impersonal statement that is said "one makes" or "you make" in English, is said "on fait" in French. That kind of statement would be said in Spanish "(tú) haces" or "uno hace", or even "se hace". However, the "on" particle is also used to express things like "En Finlande, on parle finnois et suédois", which I think would be more or less as "In Finland, Finnish and Swedish are spoken". In Spanish one would never say "En Finlandia, uno habla finés y sueco". It would mean that you know Finnish, Swedish and other languages, but when you are in Finland you only speak the former two. When you intend to say that something usually happens somewhere, you say "En Finlandia se hablan finés y sueco". I supposed that "snakker man" means that people there speaks, not that you or the speaker speak the languages. But I didn't know that in English is possible to express "reality statements" with the impersonal form. "One speaks" for "people speak". So, my doubt is, in both cases the sentence means that "people speak", am I right? Tusen takk!