I wrote, "Owl, do you speak Chinese?" and got it wrong because ...? it's someone's name? how can I tell the difference between a name and Duo's habit of addressing sentences to cats, birds and dogs in our exercises?
When it is at the beginning of the sentence, you can't tell the difference. In another sentence, where Pöllö was also at the beginning, owl was accepted, so I guess it should be also here.
Can we just omit the pronoun"sina"?
Yes, it can be omitted, but only in the first and second person. For example, it can't be omitted in the sentence "puhuuko hän kiinaa".
I was expecting chinese to go "kiinea", you know, because it is such an old language.