The Corconti or Korkontoi were a Germanic people in (2.10) of the Geography of Ptolemy

Ptolemy

Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

 (after 83 – 161 AD). They were in the vicinity of Asciburgius

Asciburgius

The Asciburgius mons or Askibourgion oros is a mountain of greater Germany mentioned by the ancient geographer, Ptolemy, of unknown location today. Ptolemy does give us enough information to speculate where the mountain probably is, saying it was between the Elbe river and the Oder river or in...

 Mountain somewhere near the sources of the Vistula

Vistula

The Vistula is the longest and the most important river in Poland, at 1,047 km in length. The watershed area of the Vistula is , of which lies within Poland ....

. Asciburgius gives away their location, as it is on the edge of the Giant Mountains range (Krkonoše in Czech, Karkonosze

Karkonosze

Krkonoše is a mountain range located in the north of the Czech Republic and the south-west of Poland, part of the Sudetes mountain system . The Czech-Polish border, which divides the historic regions of Bohemia and Silesia, runs along the main ridge...

 in Polish, Riesengebirge in German).

It is clear that the people were named after the terrain, but the identity of those people is not entirely clear. Ptolemy counted them among the Germani on grounds of their inhabiting Magna Germania. Some have hypothesized that they were Marcomanni

Marcomanni

The Marcomanni were a Germanic tribe, probably related to the Buri, Suebi or Suevi.-Origin:Scholars believe their name derives possibly from Proto-Germanic forms of "march" and "men"....

, as those people were in the region. So also were the Quadi

Quadi

The Quadi were a smaller Germanic tribe, about which little is definitively known. We only know the Germanic tribe the Romans called the 'Quadi' through reports of the Romans themselves...

; moreover, Ptolemy also lists the Quadi and Marcomanni. We know the latter were newcomers in the 1st century AD, but the residents of mountains are often hold-outs from an earlier culture.

And finally, the name is not Germanic, but neither is it Slavic or Celtic; or at least, no strong derivations in those languages have been found. Very likely, it is not Indo-European

Indo-European languages

The Indo-European languages are a family of several hundred related languages and dialects, including most major current languages of Europe, the Iranian plateau, and South Asia and also historically predominant in Anatolia...

 at all, but is Pre-Indo-European

Neolithic Europe

Neolithic Europe refers to a prehistoric period in which Neolithic technology was present in Europe. This corresponds roughly to a time between 7000 BC and c. 1700 BC...

. One might connect it to the hypothetical Urbian

Urbian

Urbian or Urian is a possible Old European or Pre-Indo-European language defined by Sorin Paliga. The Proto-Indo-European language, the descendants of which have replaced the Pre-IE language, ought not to include a root corresponding to Latin urbs, as the Proto-IE were nomadic or semi-nomadic...

 root, *K-K-, "to swell, inflate; big, huge", from which Sorin Paliga derives German Gigantes. Possibly Sumerian

Sumerian language

Sumerian is the language of ancient Sumer, which was spoken in southern Mesopotamia since at least the 4th millennium BC. During the 3rd millennium BC, there developed a very intimate cultural symbiosis between the Sumerians and the Akkadians, which included widespread bilingualism...

 kur-kur, "mountains", is related. Or from Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 cor continens, "heart of continent". Such derivations at this point are weak and speculative.

The question has been of some historical significance as a point of contention between Slavs and Germans

Germans

The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....

of the region. The Slavs appeared centuries later in the region than the Germanic tribes were recorded there.