Längenwechsel

Längenwechsel, a German term often translated as "length change" or "vowel gradation," refers to a historical sound change in Germanic languages, particularly affecting short vowels in stressed syllables. This process is characterized by the alternation of a vowel with a zero grade, a reduced vowel, or a full vowel, depending on the historical phonetic context. For instance, the Proto-Germanic short *e was subject to Längenwechsel, leading to different outcomes in modern languages.

The phenomenon is closely related to ablaut, or vowel gradation, which involves systematic vowel changes within related words, often indicating grammatical relationships like tense or derivation. Längenwechsel can be seen as a specific type of ablaut where the change is primarily between a full vowel and a reduced or zero grade. This change was most prominent in the development of the strong verb classes in Germanic languages, where the different past tense forms often exhibit distinct ablaut grades.

While Längenwechsel is a historical process, its effects are still visible in the modern vocabulary of languages like German, English, and Dutch. For example, the English word "sing" alternates with "sang" and "sung," demonstrating ablaut, and the underlying principle of vowel alternation is related to Längenwechsel. Understanding Längenwechsel is crucial for tracing the historical development of Germanic languages and for comprehending the systematic relationships between words. The precise triggers and extent of Längenwechsel can vary slightly between different Germanic branches, but the core concept of vowel alternation based on historical phonetic environments remains consistent.