"Con chim sẻ chia sẻ bánh mì."
Translation:The sparrow shares the bread.
Why does "sẻ" sound a lot like "sè"? Am I not picking up on something or are the tones sometimes pronounced differently?
Yes, the hỏi tone here sounds unclear. I think the vowel e has affected the quality of the tone. In Vietnamese standard voice, the e sound is /ɛ/ while this speaker pronounces e nearly like /eə/. This vowel deviation makes the word last longer and the hỏi tone is protracted. That is why it sounds a lot like the huyền tone.
Generally, tones are pronounced almost consistently. Of course, there are some small deviations but they're rare.
What is chia? Before it i assume is 'sparrow' and after is 'shares bread' but what chia?
Chim sẻ = Sparrow. Chia sẻ = Sharing. I guess they teach you similar words so that you can learn to differentiate them early on.
It is also acceptable (at least from a native speaker) that you can just use chia by itself to mean share (or split, in some cases)
This has got to be the most useless phrase in Duolingo Vietnamese. And that's saying something.