Well for Martina Hingis that's not too surprising: - Czech parents (and lived there till ~7) - moved to (German-part of) Switzerland: the local language is Swi

Well for Martina Hingis that's not too surprising: - Czech parents (and lived there till ~7) - moved to (German-part of) Switzerland: the local language is Swiss German, but school is in German (i.e., everyone speaks both of those) - everyone in Switzerland is taught one of the other official languages, usually German in the non-German speaking areas, and French in the German speaking areas (fluency will vary, but for instance I had 7 years of German by the end of high school) - everyone learns English these days ;) I would expect that most children who moved to German-speaking Switzerland at a youngish age would be fluent in at least 4 languages...