What evidence do scholars use to reconstruct Proto-Germanic?

Scholars reconstruct Proto-Germanic primarily through the comparative method, a technique used to deduce the features of an unrecorded parent language by analyzing related words and expressions in its descendant languages. Because no written records of Proto-Germanic exist, linguists compare forms across early Germanic languages—such as Gothic, Old Norse, Old English, and Old High German—to identify systematic patterns of sound change.12

Key evidence and methods include:

• Comparative Analysis: By comparing cognates like Runic -gastiz and Gothic gasts with Old English giest and Old High German gast, scholars can reconstruct the Proto-Germanic form, marked with an asterisk (e.g., *gastiz).2
• Sound Laws: Reconstructions rely on the principle of regular sound change, which allows linguists to account for phonological variations across different environments.12
• External Confirmation: Occasionally, scholars find external evidence, such as early loanwords in other languages (e.g., the Finnish kuningas confirming the reconstruction of Proto-Germanic *kuningaz), which validates these linguistic deductions.2
• Archaeological Context: While linguistic reconstruction is the primary tool, scholars also integrate archaeological evidence to understand the geographic distribution and historical development of early Germanic dialects.3