Now if I feel I want to say more than two sentences I type a Chnese title and use English as thecontent. Otherwise I type Chinese in the subject field.
I agree with you everyone of us needs to practivce writing in English more, but I have also found joy in writing Chinese, even during the very slow type process. Because my Pinying spelling is very poor now (used to be good), I
have to try several times just to get a character I want, and I see other characters used to be so familiar, but now I almost forget.

I would say, use whatever language you feel comfortable, but keep in mind the English writing is one of many skills you need to survive in the north america.