The Germanic languages constitute a sub-branch of the Indo-European (IE) language family. The common ancestor of all of the languages in this branch is called Proto-Germanic (also known as Common Germanic), which was spoken in approximately the mid-1st millennium BC in Iron Age northern Europe.
Prior to the Christian era the Germanic tribes north of the Alps developed the so-called runic characters. The runic texts appear on movable objects such as metal, bone and wood. The characters were often associated with pagan religion. The result was that once Christianity became the dominant religion, the use of runic characters was abandoned.
Perhaps the most celebrated turning point in the history of the German language is the work of another rebel against Rome, Martin Luther. His belief in salvation through personal faith alone, not the intermediation of the Church, led him to violate a longstanding prohibition on translating the Bible into vernacular languages. Luther had to compromise between the many different “Germans” that filled the German lands in those days, hundreds of years before there was a single German state. Luther borrowed an emerging standard used by the Holy Roman Empire, “chancellery German”, as a base with some currency in different regions. Luther’s genius was to infuse his translation with the words he heard on the street in his bit of Saxony, in east-central Germany. He obsessively asked friends and fellow scholars which dialectal words would be most widely understood.
In 9AD [Arminius, also known as "Hermann the German"] stopped a Roman advance eastward across the Rhine. At the battle of Teutoburg forest, the troublesome locals ambushed three Roman legions. As a result, the Roman borders, known as “limes” (from which comes the word “limits”) stopped at the Rhine. Whereas the Germanics took up as many Roman ways of life as they could afford, they never took up their language as the conquered—primarily Celtic—people of France and Spain had. Germanic marauders would later devastate the empire itself, but in another twist, those who settled in Italy, Gaul and Spain did in fact begin speaking Late Latin. Arminius had saved a bit of the map for German.
Records of a Germanic language not belonging to the northwest continuum have survived from the 4th century AD. Excepting a certain runic inscription, the Gothic language is first attested as the literary legacy of the Arian bishop Ulfilas (Wulfila). His fourth-century translation of the Bible from Greek into Gothic -- which, notably, predates the Latin Vulgate of Jerome -- inestimably furthered the Christianizing mission to the pagan Goths. Wulfila rendered his work, not in runes, but in a new alphabet based primarily upon that of Greek. Of his complete translation we possess only extensive sections of the New Testament, and little aside from this remains of "Gothic" literature. After centuries of expansion and conquest, the fortunes of the Goths succumbed to disasters that saw their seats in Italy and Spain destroyed in turn by Justinian and the Umayyad Caliphate, making the Goths a historical non-entity in Europe by the mid-eighth century. In the East, a community of Goths apparently survived into the early modern era, dwelling in the region of Crimea. A letter has been preserved from the 16th century recording a brief list of words that seem to be Gothic: tentatively its final attestation. Philologists have traditionally connected Gothic with two other Germanic languages, Vandalic and Burgundian, forming an East Germanic family. However, the latter are so marginally attested that there is not enough evidence to justify committing them to a particularly close relationship with each other or with Gothic. Regarding any association of the three, we may only say with certainty that they are "not Northwest Germanic."
The historically attested Germanic languages provide evidence to justify the construct "Germanic" when we find in them common innovations not shared by other Indo-European languages. It is possible that the primal seed of the Germanic languages was gently sown when an unknown number of Indo-Europeans started articulating voiceless stops as fricatives (e.g., */t/ > */þ/); later on, hitherto voiced stops lost voicing (*/d/ > */t/); and some time thereafter, aspirated voiced stops came to be realised as voiced fricatives, then later in most Germanic dialects as voiced stops (*/dh/ > */ð/ > */d/). This three-part "chain shift" is known famously as Grimm's Law and marks among the first Germanic innovations -- preserved in all languages of the family, being essential and limited to them. Further sound changes paralleled innovations in intonation, morphology, syntax, and vocabulary, increasingly differentiating Proto-Germanic as a dialect of Proto-Indo-European (PIE). During this time, it seems also to have shared innovations with other, geographically proximate PIE dialects, while they yet remained mutually intelligible. However, at some point Proto-Germanic had come to assume the character of a new language.
Out of the many West Germanic dialects, the following six present-day languages have distinctive written standards: Afrikaans, Dutch (Dutch-Flemish), English, Frisian, German, and Yiddish. Some discussion is also included here of Low German, Pennsylvanian German, Scots, and Black English Vernacular.
From the middle of the 1st millennium BC, there is evidence of Germanic populations in southern Scandinavia and northern Germany. Their migrations from the 2nd century BC onwards are recorded in history. The linguistic and archaeological data seem to indicate that the last linguistic changes affecting all of the Germanic languages took place in an area which has been located approximately in Southern Sweden, Southern Norway, Denmark, and the lower Elbe.
There are a few other words that were borrowed into West Germanic from Latin--we have seen wine (vinum) and cheese (caesum); here we should also add street (strata), which became the word for the Roman roads that still criss-cross Britain today. Some other borrowings are of interest: church (from the Greek kuriakon), which is part of common West Germanic and probably comes directly from Greek... Also kitchen, which comes from the Latin cucina--still the same word in Italian--and enters Old English and other Germanic languages very early, before 1000.
Standard English, as we have seen, is closely cognate to Standard High German. But what are the detailed relationships among English, German, and the other Germanic languages? How do we know about the earlier states of relation among the related Germanic languages? First of all, just to reinforce what we've already learned: English and German are cognate. Neither is the source of the other. Each descends from some unknown, prehistoric language which is the source of both. There must have been a primitive Germanic language that is the source of modern Germanic languages. The evidence from cognates is overwhelming--take, for instance, the site developed by Cathy Ball that presents versions of the Lord's Prayer in different Germanic languages.
Several Indo-European vowels were modified in the Germanic languages. For example, Indo-European /a:/ became /o:/. Compare Latin mater and Old English modor. Two consonant shifts occurred in Germanic. In the First Sound Shift (commonly known as Grimm's Law) the Indo-European stops bh, dh, gh, p, b, t, d, k, and g underwent a series of shifts. The Second Sound Shift (also known as the High German Sound Shift) affected the high but not the low Germanic languages, so English was not affected.
Germanic languages thus have two types of verbs, weak (regular) and strong (irregular). Strong verbs indicate tense by an internal vowel change (e.g. swim, swam, swum). The weak form is the living method of inflection, and many originally strong verbs have become weak.