Oguri, Kutriguri, Utriguri, and Saraguri were all Turcic tribes speaking Turkic languages.
Agathias — the principal historian of part of the reign of the Roman emperor Justinian I between 552 and 558 — wrote: “…all of them are called in general Scythians and Huns in particular according to their nation. Thus, some are Koutrigours or Outigours and yet others are Oultizurs and Bourougounds… the Oultizurs and Bourougounds were known up to the time of the Emperor Leo (457–474) and the Romans of that time and appeared to have been strong. We, however, in this day, neither know them, nor, I think, will we. Perhaps, they have perished or perhaps they have moved off to very far place.”
Click on the link below to see, where the cited tribes lived, whether they had “perished or moved off to very far place“.
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Today Slavic languages are spoken in Eastern Europe, in countries like Russia, Poland, Czech, and Serbia, to name a few. But almost a thousand year earlier there lived Slavic speaking tribes close to today’s Netherlands. See the map below and compare it with today’s political borders.
But around AD 400 the Germanic tribes were on the move allover Europe, as can be seen in the map behind the link below.
Celtic languages are those ancients with long history. They are nowadays spoken principally in Wales and on the countryside in Western Ireland.