Isogloss

A isogloss ( portmanteau on the type of isobar or isotherm, from Greek ἴσος isos, equal to ' and Greek γλῶσσα, glossa, tongue, language ') is the line in a linguistic atlas, which marks the boundary between two versions of a linguistic feature.

A linguistic feature, for example, the pronunciation of a consonant or vowel (China: [ çi ː na ː ], [ ʃi ː na ː ] or [ ki ː na ː ] ), a grammatical form, use and meaning of a word or the like. Such linguistic features are also known as linguistic variables. Important isoglosses of the German dialects are the Benrather line, the Speyer line and other lines of the Rhenish fan.

In more recent language atlases and different colors for the different characteristic values ​​are used instead of isoglosses. The isogloss or the " Isoglossenbündel " is then the edge of a color zone. If a particular feature expression appears only in one place or in a very small area or sporadically, it is marked by a symbol, a letter or a number.