Any confirmation for the break up of Tartar/Altaic Cultures in Late Game to create all those cultures present during the first start date of EU4, say for example:
- Astrakhani
- Bashkir
- Crimean
- Kazani
- Mishar
- Nogai
- Siberian
As well as rethinking East Slavic cultures, where instead of all becoming Russian they actually subdivide into 3 general cultures into each of their 3 general regions:
- Byelorussian
- Russian
- Ruthenian
"Tartar/Altaic" is a tough nut to crack because CK2 already goes broad-strokes with Turco-Mongolic cultures. This is especially true because many of these groups don't become distinct cultures until well after CK2's timeframe. For ex, it's hard to describe the Nogais as a specific culture in most of CK2's play space; they're of the Mangghud tribe of Mongols. But many of the origins of these groups are very obscure. For ex, the Naimans - they're Mongols in CK2, but in reality they were probably originally Turks from a group called the Sekiz-Oghuz, who adopted a Mongolic language. Or maybe they were related to the Yenisei Kyrgyz. Or maybe they were related to a Siberian people called the Az. Or maybe they popped out of a hole in the ground. Many of these guys we just do not know, but we can broad-stroke it.
I'd divide the steppe cultures up this way, myself:
* West Turkic culture group: Oghuz, Pecheneg, Khazar, Bolghar. (Oghuz Turks who convert to Islam and hold an Iqta county, or are in Persia, get a melting-pot event to form Turkish.)
* East Turkic culture group: Kipchak (Cuman), Kyrgyz, Karluk, Uyghur.
* Mongolic: Mongol, Naiman, Oirat, Khitan.
* Finno-Ugric: Magyar.
* Iranian: Alan. Avar?
Byelorussian is also anachronistic for this period, but I could see Ruthenian. For the most part, the "Russians" in CK2's time period would've spoken Old East Slavic until some divergence in maybe the 1200s, when you started to see a form of Old East Slavic which took on Polish and Lithuanian influences. I can see Russians who are Catholic, or vassals in a Polish or Lithuanian realm, or holding a Polish or Lithuanian province, receiving a melting pot in which the Ruthenian language begins to take shape.