Ik gihorta dat seggen,
dat sih urhettun ænon muotin
Hiltibrant enti Hadubrant untar heriun tuem.
Sunufatarungo iro saro rihtun,
garutun se iro gudhamun, gurtun sih iro suert ana
helidos, ubar hringa, do sie to dero hiltiu ritun.
Modern German Language
Ich hörte (glaubwürdig) berichten,
dass zwei Krieger, Hildebrand und Hadubrand, (allein)
zwischen ihren beiden Heeren, aufeinanderstießen.
Zwei Leute von gleichem Blut, Vater und Sohn, rückten da ihre Rüstung zurecht,
sie strafften ihre Panzerhemden und gürteten ihre
Schwerter über die Eisenringe, die Männer,
als sie zu diesem Kampf ritten.
Alothochdeutsch was the first form of the |German language and it can be called Old German. It existed from 500-1000 CE. It is probably somewhat analogous to Old English, but I doubt if the two languages would have been intelligible. The passage above is from 900, written about the same time as Beowulf was written.
It is truly amazing how much German has changed. Old German for all intents and purposes is a completely different language. The two languages look nothing alike at all and there is no way that modern Germans would understand a passage spoken in Old German. In that sense they are analogous to the relationship between English and Old English.
The modern German language called Hochdeutsch or High German is based on the language that Martin Luther used in his Bible translation. Luther was from Saxonia and the language he used was an Upper Saxon dialect modified to make it intelligible to as many Germans as possible.
Presently Standard German is a mix of Upper Saxon and Thuringian spoken with a Northern German accent. No one ever spoke this way naturally as part of their dialect from their home region. For hundreds of years, Hochdeutsch was only a written language. Various German writers used variations of it to try to make their written German as intelligible to as many Germans as possible.
Only around 1800 did Hochdeutsch begin to be used as a spoken language. At this time it began to be taught in schools and for a long time, German students learned it as a what amounted to a foreign language, their first language being whatever German dialect was spoken in their region.
In the 20th Century, Hochdeutsch began to be a common first language for many Germans who grew up speaking it either alongside their regional dialect or instead of the dialect. It was also during the past century that Hochdeutsch began t supplant many German dialects. The truth is that many German dialects are not dialects at all but instead they are full blown language in terms of both intelligibility and structure. Ethnologue lists 20 different German dialects as separate languages and the truth is that there are many more than that.