Dachsprache means a language form that serves as standard language for different dialects, mostly in a dialect continuum, even though these dialects may be so different, that mutual intellegibility is not possible on the basilectal level between all dialects. In 1982 in Switzerland Romansh (by then called "Rumantsch Grischun" by most of it's speakers) was successfully created by Heinrich Schmid as such a Dachsprache for a number of quite different Romance language forms. Standard German to some extent functions the same way.
