Old German High Language

The language in use from 500-1300, about three hundred years.
We have one one written version of the language, this dictionary made by a monk to translate language into and out of Latin.

A belt with inscriptions was also recovered from another site. No one knows what kind of writing was on the inscription. Old High Germans was mainly a vocal language, likely a straight shot from IE, and it was the language used when Germans began migrating west and south.

By this time we had late Latin, not the early stuff, but the Christian monks were the new scribes. We can see them carry on the tradition, using Latin as a dictionary language.