The Finlandssvensks speaks Swedish as their native tongue. The pronounciation differs, however, from "rikssvenska", the Swedish spoken in Sweden. A large portion of the officially Swedish-speaking people are bilingual with their other language being Finnish.
It should be noted that Finland has two official languages, Finnish and Swedish. The Finnish-speaking Finns sometimes confuse the Finnish-Swedish with Swedish people, and therefore many Finnish-Swedish like to emphasise that they are in fact Finns and not Swedish.