Translation:In Switzerland one speaks German, French and Italian.
Should it be "or" rather than "and" (do all Swiss speak all these 3 (4) languages)?
Most of us speak 2, if not 3 of the National Languages! ;-) But I think it's still "and", since it says all 3(4) languages are spoken in the country, not spoken by a person in the country.
Actually, the sentence says, "...one speaks..." not "...languages are spoken..." If it were the latter, and would be acceptable. As it stands, renska is correct and the sentence would be more accurate as: "In Switzerland one speaks German, French OR Italian." Check out the link regarding Boolean operators.