miniCruzer, add \b anchor to every of your regex matches like this:

/(\bbola\b|\bComo\b|\bvai\b|\bvocê\b|\bbom\b|\bsim\b)/iS

This will greatly minimize the chances of being triggered wrongly if any word or letter said within the matching text. And remove the dollar sign at the end of them.

I think it's rude and arrogant to laugh at people's scripts without giving his or her suggestion for improvement.