"The man and the woman are talking."
Translation:Mannen och kvinnan pratar.
I had the same question and looked it up. It seems like they mean the same thing, but talar is more formal and old-fashioned.
As far as I can tell—and please correct me if I'm wrong—whether the subject is singular or plural, for present tense Swedish verbs you never add "är" to the verb, even though in this case it sounds like what you would say in English ("They are talking"). "Pratar" by itself (no "är") can mean any of the following: talk/talks/is talking/are talking.