It seems like an extremely coarse classification. Category 3 contains languages with very different degrees of difficulty, while Bulgarian and Russian are both Slavic they are nothing alike in terms of difficulty since Bulgarian is the most analytic of Slavic languages (has the less inflection). That makes it extremely easy to learn compared to Russian.

What is also interesting is how written Russian was heavily influenced by old Bulgarian. In fact, written russian includes a lot of older written bulgarian vocabulary.

This results in a weird paradox: for literate Russians it is easy enough to read written bulgarian but almost impossible to understand the spoken language.

This happens in other languages too - danish and Norwegian are almost the same written, such that most products just combine the two on the packaging. But spoken it can be very difficult to comprehend

I speak Russian and some Bulgarian as third/forth languages, and while I agree that Russian is more difficult, I wouldn't say Bulgarian is "extremely easy" in comparison. It's maybe ~20% easier at best.

I think Bulgarian is considered the easiest Slavic language in terms of grammar because it has a simplified case system similar to how English dropped its cases over time.

On a superficial level that seems like a roughly correct ranking in my experience. On the other hand, I picked up one of the category 3 languages pretty easily. I think some of these are more "weird" to a native English speaker than "hard" per se.

The aspects that make languages difficult for a native English speaker vary quite a bit with the language. I would expect individual experiences with the languages to have high variance as a consequence.

Difficulty scale looks about right.

As others hsve pointed out, it's a very coarse (and rather arbitrary) categorization.

E.g. both Turkish and Russian are in Category 3, but Turkish is trivial compared to Russian.

Turkish grammar is extremely regular, and follows easily defined rules that fit about two pages of easily digestible tables.

In comparison, Russian is a separate class tought in Russian schools for four years to native Russian speakers. And you still get people who can't properly inflect numerals, for example.

Turkish has a completely different vocabulary (loanwords aside) and a completely different grammar.

"I want to swim" in Russian is "ja hoću plavatj", "I" + "want" + "to swim". The only difficulties are the conjugation of "want" and the aspect of "to swim". In Turkish it's "yüzmek istiyorum", where "-mek" is "to" and "-um" is "I". Even if the system itself is straightforward, it's still alien to a native English speaker.

> Even if the system itself is straightforward, it's still alien to a native English speaker.

As a native Russian speaker who speaks English and Turkish:

The question isn't about alienness. It's about difficulty. Turkish is trivial compared to Russian. You can learn all the grammar rules you'd ever need in a week or so (though most study materials make it harder than necessary). The rest is just learning vocabulary. Which is just as alien to an English speaker as Russian.

As for the example...

Here's a valid three word sentence in Russian: Ya idu domoj (I'm going home).

Depending on context, mood, feel, etc. any permutation of those words is a valid sentence: ya domoj idu, idu ya domoj, idu domoj ya, domoj ya idu, domoj ya idu.

And that's before we get into inflections, conjugations, gender etc. that neither English nor Turkish have. Or somewhat arbitrary pronunciation rules (korova is pronounced kahrohva) whereas in Turkish every word is pronounced exactly as written (with very few quite regular contractions in regular speech like yapacağım -> yapıcam) etc.

> The question isn't about alienness. It's about difficulty.

The original link is specifically about difficulty to native English speakers, which is certainly linked to its alienness.

Turkish is regular, has well specified rules you can learn in a week, is extremeley easy to read (pronounce as written, there's no floating/jumping/changing stress). Oh, and the alphabet is latin-based.

Russian: extremely complicated grammar using concepts entirely alien to English (declensions, inflections, conjugates, grammatical cases, genders, transgressives, and even plurals are weird), has free-form-not-really sentence structure, jumping stress. Oh, and a completely different alphabet to boot.

"the alphabet is Latin based"

Yes, phonetic spelling but you won't be able to read anything much before WW1.

As if that is a required criteria for learning Turkish, or for assessing its difficulty.

Note: 99.9% of Turks are not able to read much of anything before WW1.

Exactly. Historical amnesia which is partly what Kemal Atatürk was after. Year Zero.

Isn't English also a separate class taught in English schools to native English speakers?

Not always well. One of the problems is that English speakers do not get taught the proper parts of speech. I learnt far more about English from learning other languages than I ever did in English class. We would get told off for bad spelling and grammar, but very little on the actual mechanics.

English classes (at least at my high school) were largely about literature, less the language itself. Though I did take one elective class on grammar.

Yes.

All through middle and high school, so for 7 years from around 10 to 16. It did become one eventually in primary school, so probably the last 2 or 3 years there.

Not for four years, for all eleven years...