English and Chinese. My Chinese is much worse than my English though, as I grew up speaking it as a “home language” only (born and raised in America to Chinese immigrant parents) and have close to no formal education in it, so my vocabulary is very limited compared to my mastery of English, and I am functionally illiterate in Chinese. I am able to carry on casual conversations on social topics with relative ease and with a native or near-native accent (until I exhibit some kind of vocabulary gap, strangers often think I’m from Taiwan).
In terms of separating the languages, it’s contextual and there is often code-switching involved to plug the vocabulary gaps - or even when the vocabulary is known in the other language, if it’s just more natural to say it in English or Chinese to someone else who knows both. For example, I always want to say familial terms and terms for food in Chinese when speaking with Chinese-American friends of my generation (assuming they know Chinese) because it just feels weird to refer to “my uncle” when the Chinese term clarifies if he’s my father’s younger brother or my mother’s older brother, or to say anglicized versions of food terms, especially when they’re anglicized pronounciations of the Chinese term.
More interestingly, I apparently “revert” to Chinese in specific kinds of stressful situations in a kind of flashback to childhood. It’s happened a few times. Here’s the best example:
Cut me off in traffic and I will swear in English. I know this, because it is a regular thing.
A few years ago, when a large green spider streaked across my computer keyboard late one night, I also yelled in English (“what the f*ck --?!”) while grabbing a nearby magazine and smashing it into a crumpled, leaking heap with a quick stroke.
But when I went to clean up said spider with a napkin fetched from the kitchen, fifteen minutes later, and it twitched, revived and ran up onto the back of my hand, I yelled in Chinese the equivalent of “OMG IT’S STILL ALIVE!!!”. It just came out. (I didn’t say it, but I suppose there was a subconscious addition of “Mom!!!” or “Dad!!!” somewhere in there, eh?)
And just a few days ago, it happened again, when my cat slipped into my bedroom while I was in the shower in the morning getting ready to go to work, and deposited a dead mouse on top of my dark dress socks where I had them laid out on the floor. Hoo boy.