This is common in South Tyrol too. There even the ordering, what goes first, German or Italian name of the place changes. A quick guess, it depends on majority from the most recent census.
The americana map shows me the German name only, for minor cities, but the German name and the name with the space separated dash/minus in parentheses for the single major one. Perhaps, because my browser is configured in a way, that I prefer German names and this is a vector map, that can do individual display.
However, a semicolon for names will not fly. Not for OSM-Carto and not for americana. Another quick guess: How about a key that lists languages in order of preference of the local community: name:scaffolding=de;it e.g? So a consumer might choose from name:language=* to meet their users preferences and not have to rely on *name" at all (if present)?