Complex sentence: Lángos is sold at many fast-food restaurants not only in Hungary but also in Serbia, where it is known as "languš" and has been introduced by the Hungarian population of Vojvodina, in Austria and the Czech Republic.
Split into simpler sentences: Lángos is sold at many fast-food restaurants not only in Hungary but also in Serbia, where it is known as "languš". In addition, it has been introduced by the Hungarian population of Vojvodina, in Austria and the Czech Republic.