Sentiment Keyboard

Sentiment Keyboard is a keyboard designed to make you more aware of the potentially offensive things you might be saying on a daily basis. The send/enter button has been replaced with a "check" button which will read what you have just written and analysis it for offensive content. Don't worry though, to hit enter, all you have to do is long press the check button.

And it's open source!
That means you can take the app and change it however you want, just head over to https://github.com/jacobrec/sentiment-keyboard