Ottawa, Ontario, Canada English is my main native language. It is probably beyond CEFR C2, as I read Wikipedia/academia/technical/journals in it
Wu Chinese is the first language I was exposed to, but I mostly only used it with my parents and a few families from church. Any words beyond commonly used expressions or grammar I just use Mandarin words with a Wu pronunciation. The ".z.tg" part of my name is from Chinese.
My parents sent me to Chinese Saturday school. I learned how to speak, but I can barely write. I watched TV shows in Chinese with my parents. Then I relearned Hanzi from Korean and Japanese. My knowledge here is in a polar opposite situation compared to my English. Most of the Chinese I know is vulgar, street, and colloquial, and I struggle with formal/business terms.
I learned just enough Classical Chinese to read, and while reading literature from Ancient China. Parts of it may leak into my Modern Chinese, making it a strange mix of vulgar and learned terms that someone would never use in a business meeting
I only a few Cantonese words in writing, and the limits of my formal phonology understanding is knowing the different tones. I have been exposed to my parents playing Cantonese songs and TV shows, and a bunch of my friends from church and high school spoke it around me
I took Core French in primary and secondary school like everyone in Ontario. I am currently learning more French to improve my job opportunities working from people from Quebec. I can read emails and understand 90% of what my coworkers say, but I take too much time trying to find my words while speaking
Spanish, Russian: I set aside after just the first few courses on Duolingo. I know most Cyrillic letters for Russian, but I may conflate them with other Slavic Cyrillic letters
I only know Italian to derive piano English terms and French terms
Sanskrit I don't know and can only derive from PIE etymology. I know only the Devanagari to analyze PIE
I leaned IPA for Korean. Then I used IPA to transfer my French pronunciation knowledge into learning Ancient Greek. I focused mostly on vowels
I know Latin from LLPSI, Duolingo, and PIE. I use Latin to unify my English and French knowledge and be able to sight read other Romance languages
I barely know any Ancient Greek from LGPSI. I use it to help learn Latin and PIE. I hope to read the Koine bible someday
I memorized a bunch of stuff about PIE from Wiktionary and Wikipedia. I use PIE to unify my Latin, Ancient Greek, and Sanskrit knowledge, as well as figuring out the roots which usually give the main idea of a word or its derivations
I can read Hangul and Korean UI strings from gaming Twitch streams, but I can't read sentences well as I haven't started really studying
I am JLPT N1 in vocabulary (highest test before Kantei) in Japanese