Earlier quoted context omitted.
My first language is Russian. I learned English from 12 to 14 to a basic level and from then came to the US and learned the rest of what I know here. Some thoughts: 1. English has a very simple, pre-defined sentence structure. Run-on sentence are discouraged. The language has almost logical decisions regarding the use of the verb “be”. Words are rarely skipped because they are implied. By contrast Russian is much mor…
2. Two short sentences here don't accurately convey the horror of Russian's case system, where not just verbs but also NOUNS must change (decline) into one of 6 main cases (potentially more depending on whether you consider the locative, partitive genitive, vocative, etc. as distinct cases) :D, but yes absolutely - basically, you only ever have the possessive form in English 'add 's, or for pronouns just learn 'his/h…
Hardly a 10/10 for the BDSM part. Whilst the Russian language has retained many grammatical features of the Proto-Indo-European language, it has also dropped many (i.e. perfect tenses, the aorist, a number of noun cases, merged long, short and ultra-short vowels into same quality vowels and lost all nasal vowels and the list goes on). Russian, whilst having its own share of linguistic quirks (but, hey, what language does not?) is no more complex than, say, Sanskrit.
For the purpose of inflicting severe bouts of pain in the rear orifice, give Basque (an absolutive-ergative language) or Georgian (a Kartveli language with the split ergative) a go. Both have no known language ancestors, both are highly agglunative languages with some serious phonetic challenges and with a wealth of deliciously mesmerising grammatical peculiarities.
Or try native highly agglunative North / South American (e.g. Navajo for agglunative and fusional delights and the tenseless verb conjugation by 7x modes and 12x aspects of each mode and Quechua for reversed concepts where future is placed «behind» the past which is always «ahead»), or Innuit, or North-Caucasian languages. Russian will feel like a godsend and a breeze after that.
Then, there are Klingon and Lojban.