I'm currently learning Polish and I'm doing really well with it so far. Such a cool language, by the way. However, I want to learn Russian as well, I love both the languages and I would love to learn both. Is this a good idea? Has anyone here learned two languages simultaneously?
I consider myself quite good at learning languages, it's something I find very easy. For GCSE exams, I learned a lot of French and German together and never confused the two.
Well, if you have the time and the wits for it, just do it! Else better focus on one language. Concerning grammar, there are many parallels in Slavic languages, but the Cyrillic alphabet might be an obstacle (will take several months to learn it properly, I guess). More I will answer in: which is harder: pole learning russian or russian learning polish?
Sonorous, French and German are two SEPARATE languages from within the identical Indo-European family, whereas Polish and Russian are closely RELATED languages from within the SAME family. French is Romance, German (like English!!) Germanic, whereas both Polish and Russian are Slavic:-)
Having tried to learn both simultaneously, with disastrous consequences for my Russian, I'd strongly advise against it. This though is only my point view!
I learnt everyday Russian from my grandma up until I was around 9 or 10 and didn't make much use of it since I moved to the UK at the age of 12 because I had to struggle with German, Spanish and a little French for GCSEs and A-levels. Then I started learning Polish when I turned 18, and I was in for a surprise! My childhood knowledge of Russian helped me loads with learning Polish. As Marek already mentioned, you will find many similarities in terms of grammar (although I personally find Russian grammar a tad more confusing). If you feel confident with Polish grammar (which is often very difficult for native English speakers) Russian counterpart shouldn't cause you too much troubles (except for numbers, telling the time, etc.)
The only thing other than the Cyrillic which could be difficult in learning Russian is the pronunciation irregularity, which is hardly observed in Polish. Words that are same or similar in the two languages quite often have accents on different syllable (take the word Wednesday for example. Emphasis falls on the last syllable 'da' in Russian, supposed to 'ro' in Polish). Without help of good audio materials or most ideally a native speaker (or a dictionary with written out accents) it would be quite challenging to know how the word should actually be read.
Nonetheless, both languages are really beautiful and as I see that you like them, I would say go for it ;)
Of course, it's usually a question of the learner's age. I, for instance, was raised basically bilingual German/English, NOT Polish, which I didn't actually "study" until age 30!!! I suppose had I started off, say even in grade school, with Polish, then Russian, I could in fact have learned them both fluently. Starting one's first Slavic language as an adult, PLUS balancing the workaday demands of marriage, family, work etc... in addition to the burden of yet a SECOND Slavic language on top of the one I still didn't know one hundred percent, was just a little more than I could handle at the time:-)
The Cyrillic alphabet should take you about 90 min. to learn. Certainly just memorizing the characters (some of which are the same as the English alphabet) isn't a massive undertaking. It may take you a bit to get used to sounding out the words but it gets easier. As for the endings, yes, in a lot of cases they have the same or similar sounds, fine for speaking a bit messily but a disaster if you want to learn to translate precisely. You find yourself wondering if it's the same or different than the other. I think the Russian accent is a bit more difficult to master (not that my Polish accent is anywhere near perfect). The "soft sign", for instance, changes some of the sounds.
Russian's palatalized consonants "d" and "t" I still find oodles tougher to pronounce than Polish:-) I've said all this before, but it's still true! I can HEAR the difference between "brat" (brat = brother) vs. "brat' " (brać = to take) etc..., I simply can't reproduce the difference adequately for any Russian native speaker to take my Russian language seriously.
Learning Polish and Russian together is a great idea! About 60% of both languages are the same, and you get to knock down 2 languages at the same time! "Kill 2 birds with 1 stone".