Translation:The firefighter speaks American English.
As an American who has lived and worked with British people, there is a definite difference. We even had a British to American dictionary in the international school library where I worked in Hamburg Germany. (That is were I discovered why I shocked my British 3rd graders when I told a girl to "get up off her fanny and get going". ;->)
Using "talks" with a direct object sounds strange and unnatural to me, except for what feels like a specific colloquial usage, such as "to talk business/money". However, Merriam-Webster does list a possible transitive usage of "to talk" for "using a language to communicate" (like "to talk French") so it must just be my specific American dialect.
I guess it's also possible that "to talk" doesn't describe the general ability to speak a language like "to speak" does; I can't confirm because I've personally never used "talk" like this (and I also don't know whether the Swedish sentence could be specifically implying only the general ability and never the current action).