There is an argument that stereotypical ethnic Russians are Finno-Ugric people.

Moreover, if you go almost anywhere in Siberia, 50% or more of the locals will be of ethnic minorities native to the area (you may describe their appearance as Asian). More in rural areas. Many regions are dual language, Russian + indigenous. This includes the largest administrative region on Earth that is not a country.

> ethnic stereotypical Russians are Finno-Ugric people

They speak Russian, a Slavic language. The culture is clearly linked and descended from the Old Slavonic people.

I'd love to know about the thinking as I'm scratching my head here. This is the first I've heard this claim and I am half Finnish, quarter Russian by ethnicity. My grandparents certainly did not think they were from the same ethnic group.

> They speak Russian, a Slavic language

Modern Russian is a little bit older than hundred years.

"Pre-reform" language was significantly different in script, vocabulary and grammar and wasn't older than hundred years itself. Before Napoleonic war 1812 nobility was speaking French, ruling family was German and serfs were speaking Polish, Belarusian, Ukrainian or one of the Turkic dialects.

The only slavic parts remaining in the modern Russian is Cyrillic script and words borrowed from Ukrainian.

Not exactly true. The Bible was translated into Russian in 1820 so we have a pretty good idea of what Russian language was like back then (99% similar to today’s language). There were a few minor changes to the script, but nothing crazy.

The first argument is theoretical and controversial. The second point is not.

What part of Russian being a Slavic language is controversial?

Poster is not saying that — they are answering the immediate parent’s question, not analyzing his arguments, and instead analyzing the two arguments of the grandparent post.

The phrase "Grattez le Russe, et vous verrez un Tartare" (Scratch a Russian and you'll find a Tatar) wasn't invented yesterday.

"Slavic Russians" are mostly Belarusians (Smolensk Region) or forcibly assimilated Ukrainians (Bryansk, Kursk, Voronezh) or not even assimilated Ukrainians in Kuban (they still speak Ukrainian, but have their own name for it).

Russians are just one of dozens of nationalities in Russian Federation.

They may be considered Slavs but the reality is many of them are more Mongolian and very different from Slavs. Even their language shows signs of Mongolian influence. The Mongolians could not pronounce certain sounds properly and the Russian language exhibits these pronunciations.