High German consonant shift

The High German languages are subdivided into Upper German (green) and Central German (cyan), and are distinguished from Low German (yellow) and the Low Franconian languages. The main isoglosses – the Benrath and Speyer lines – are marked in black. This map shows the modern boundaries of the languages after 1945.

In historical linguistics, the High German consonant shift or second Germanic consonant shift is a phonological development (sound change) that took place in the southern parts of the West Germanic dialect continuum. The shift is used to distinguish High German from other continental West Germanic languages, namely Low Franconian (including standard Dutch) and Low German, which experienced no shift. The shift resulted in the affrication or spirantization of the West Germanic voiceless stop consonants /t/, /p/, and /k/, depending on position in a word. A related change, the devoicing of the voiced stopped consonants /d/, /b/ and /ɡ/, was less widespread, and only the devoicing of /d/ is found in most dialects.