I’ve been speaking pure Chinese for almost an entire week straight. Certain muscles in my tongue that I didn’t know existed are tired. People tell me they’re surprised at how good my Chinese is — not just in terms of pronunciation, but vocabulary as well — and wonder how it’s possible without any means of practice. I can’t explain this myself, aside from a constant interest in learning new terms, and a love of Chinese movies (although this is more of a love of Hong Kong, and Chinese movies are my sentimental way of revisiting it). There are also some Chinese terms that have no English equivalent, and people are always shocked when I know them.
Somehow, I can switch between the languages quickly when I’m here. I even catch myself counting in Chinese now, which they say is what reveals your mother tongue.