controlling my tongue

I have been stuggling with this weakness of mine. It is so tempting to bad-mouth others, especially when it is justified. When we get together for breakfast in the morning, someone will start and I would be so tempted to jump in and provide the necessary input to generate laughter or sadness, etc. All this at the expense of the person being talked about. I do not want to do this. Often, after the event, I would feel bad, an aftertaste in the mouth and I would not know the reason until after much soul-searching. Then, I realise that I just could not control my tongue. I really must resist the urge to add, subtract or to impress thru my gossips, no matter how juicy or how right the gossip is.
For I have been burnt before and yet, I do not learn my lesson. I need to submit this area of my life to God and ask Him to grant me strength..to lose interest, to be wiser and to only speak whatever is helpful, encouraging and inspiring.