Röstigraben

Röstigraben (German pronunciation: [ˈrøːstiˌɡraːbən]; literally "Rösti ditch" or "Rösti trench" also transcribed Röschtigraben to reflect the Swiss German pronunciation [ˈrøːʃtiˌɡrabə]) is a term used to refer to the cultural boundary between German-speaking Switzerland and Romandy, the French-speaking parts.

[2] Graben has both the concrete and abstract meaning of "rift", with the Saane/Sarine river valley in the bilingual canton of Fribourg separating the linguistic areas.

The Swiss-French use a similar expression: barrière de rös(ch)ti, literally "rösti barrier", or rideau de rös(ch)ti "rösti curtain" (reminiscent of the Iron Curtain).

By analogy, the term Polentagraben is used to refer to cultural and political differences between Italian-speaking Ticino and German-speaking Switzerland.

[3] The canton of Ticino is seen as having a tougher stance towards migrant workers and a greater attachment to the notion of Swissness.

French (green) and German (orange) language areas of Switzerland
French and Local Germanic dialect in the contact zone at the so-called "Röstigraben"
The Sarine in Fribourg