You should run the phrase through Chinese more often. Google Translate is horrendous with that language. I just had two Taiwanese exchange students over at my house for a few weeks, and they had a game of watching Google return garbage even with simple phrases.

In particular, "I am happy" gives back "I'm happy" in every case -- except when Chinese is part of the loop. Then, it translates to "I'm very happy."

Nice web app, though. It reminds me of Translation Party, which went viral on Reddit a while ago.