None. I can read Hangeul, but don't understand enough to read raw manhwa. I've successfully read raw manga before because they put furigana on everything, but I can only read maybe 10% of real life Japanese.

When I was a kid I could fluently speak another language. I remember none of that, but several people who knew me then testify to this. Alas, English is my only language now.

I tried to learn Japanese but never got there... I am only fluent in Russian and English...

My ability to speak English drops but I unlock the ability to speak my native language when I'm drunk. Perhaps my problem was not being drunk while trying to learn.

The only language I can read and write is English. And I can't even do that well xD

I don't call it proficient, but I've been studying Japanese at a snail pace for around six years. I think I could learn faster with more motivation. Whenever I'm able to read or translate something without help, I feel triumphant! Writing is hard, though. I understand a lot of spoken words but I can't write them without learning loads of Kanji.

Very much depends on what is meant by "proficiently".
There is no objective, or agreed upon, standard, for what counts as "proficient" ...nor "fluent".
What one counts as proficient, another counts as utterly unproficient
...and what one deems not nearly proficient, another deems proficient.
(the same being true, if one replaces "proficient" with "fluent" )

Thus, the poll is very inaccurate.

I'd say I'm most certainly not proficient ...but would everyone agree, with that assessment? I've never been to Japan, but I suspect I'd manage to understand/communicate basic stuff reasonably okay, in Japanese, if with some occasional effort?

I've not been able to take a Japanese class, but with a bit of slow and occasional attempts at learning it, over more than twenty years... I've picked up a thing or two.
Though not in the "stable"/"proper" progression you'd get, with proper education, but kinda... fragmented? I lack some rather basic knowledge, but also have some know some stuff that is very advanced, I think...

I can read a lot of manga, raw.
I sometimes read something raw, to practice/challenge myself. Sometimes because there is no translation. Sometime I encounter a meme/photo/whatever that has no translation, sometimes I read a bit of a manga I've read translated, in the original...
And in some cases, I deem the scanlation to be insufferably bad, and just go with the raw.
Which has mostly worked out okay.
I can't quite manage anything or everything, but most stuff tends to be okay, with the occasionally need to consult a dictionary, though I'm sometimes not quite sure I understood what was said, even with that.

Pure text books still scare me, but I really should try to take on some relatively easy ones.
I can handle some Japanese websites, with the help of rikaichan. (or similar extension)
Not always, of course, and it does take some time and effort...
When I read something on Japanese Wikipedia, I often first check it Google Translate, and then properly check the more important (and/or more badly Google Translated) bits. Machine translation is quite atrocious, of course, (which can be rather amusing) but it does give you some idea of what is said.

Now speaking/writing is, of course, quite a different issue, and a lot more difficult.
I'm not very confident, when it comes to that ...though I should be able to manage basic stuff, I think? That is, manage to be understood. Not necessarily for my Japanese, to be quite correct.

Just Japanese. A little Chinese but I haven't worked on that for years although I do intend to eventually. As it stands my classical Chinese is still better than my modern Chinese. Not very convenient. Sometimes I find myself reading manga in English because I can't find the raws anywhere.

I used to be able to read and write Mandarin on a not-quite-beginner but not-quite-fluent level. But what you don't use, you lose, now I only remember a few spoken words and phrases. Once I finished intermediate Mandarin 2, I never continued, and that was in 2010. I would like to re-learn it.

Not proficient or fluent in Korean or Spanish, but my goals when learning both of those languages was just reading comics/books. Every teacher that I've ever had, declared that my learning abilities would be quite stunted if I did not take time learning how verbal speech works. But alas, I still don't care, and continue to study reading comprehension.

I am proficient at reading comprehension in the Spanish language, but my comprehension abilities in Korean is bad. I know how to read; I just need more vocab. The vocab you get from reading particular genres aren't always applicable elsewhere.

Picked none because while I can read and comprehend Japanese enough to read a pretty straightforward romance or slice of life manga, it takes a certain amount of effort and motivation to do it (i.e., only have access to a Japanese copy of the work). Contrasting this to the languages I can "glance" read (like I could glance at the page and get some context because my brain just recognizes the words and absorbs them because they stick out), definitely not proficient.