Italienisch

(aber dAlla casa, nicht dElla casa).

http://www.proz.com/kudoz/english_to_italian/idioms_maxims_sayings/1024384-drinks_are_on_the_house.html

http://dict.leo.org/forum/viewUnsolvedquery.php?idThread=698525&idForum=29&lp=itde&lang=de