Proto-Germanic

No text in Proto-Germanic survives, because the language had already begun splitting into its daughter branches, East, North and West Germanic, by the time any Germanic people wrote anything down. Everything known about it is reconstructed by the comparative method, working backward from Gothic, the earliest well attested Germanic language, recorded in Bishop Wulfila's fourth century Gothic translation of the Bible, together with Old Norse, Old English, Old High German and Old Saxon, comparing shared and divergent sound patterns and vocabulary to infer the common ancestor form beneath all of them, and cross-checking the result against Proto-Indo-European, from which Proto-Germanic itself is judged to descend. This method identified Grimm's Law, the systematic consonant shift, first Indo-European voiceless stops becoming Germanic voiceless fricatives among other changes, that separates Germanic from its Indo-European relatives and gives words such as English father and Latin pater their related but shifted initial consonants.

Linguists date Proto-Germanic's unified existence to roughly the middle of the first millennium BC, based on the degree of divergence already visible among its earliest daughter languages, though because it was never written the dating rests entirely on internal linguistic evidence rather than any external record, and reconstructed forms are conventionally marked with an asterisk to signal that they are inferred rather than directly attested.

Reconstructed Proto-Germanic vocabulary underlies much of what can be said with any confidence about pre-Christian Germanic religion, since the alternative, medieval Christian sources such as Snorri Sturluson's Prose Edda, were written centuries after conversion by authors working at a real remove from the beliefs they described.

The historical runic alphabet, the Elder Futhark, is itself named through Proto-Germanic: its first six letters spell out futhark, and its individual rune names, reconstructed forms such as fehu, cattle or wealth, and wunjo, joy, are Proto-Germanic words rather than later inventions, giving each rune a claim to genuine period meaning rather than only a later reinterpretation.

Several major Norse deity names are likewise reconstructed to Proto-Germanic roots shared across the wider Germanic world rather than invented fresh in Scandinavia, most notably *Wodanaz, ancestor of both Norse Odin and Old English Woden, whose wide geographic spread, attested in place names and the weekday name Wednesday across Germanic Europe, argues for a cult considerably older and more widespread than the Old Norse sources alone would suggest. Because so much of Germanic pre-Christian religion is known only through later, Christianized retellings, this linguistic layer, words reconstructed rather than texts transmitted, is often the most direct surviving evidence of what the older tradition actually called its own gods and rites.