Are these people your friends, family, fellow Christians, or worldly people you meet at work or school? Depending on who they are will make a difference on what you should say.
I have a friend who also likes to talk down about people. He doesn't gossip, but constantly judges other people. It can be difficult to talk to our friends when they are sinning. We love them and want them to stop it, especially when they do it around us. And yet, when we try to talk to them, they become all defensive. They say stuff like, "Who do you think you are?"
Before doing anything, make sure that you goto Jesus in prayer and ask Him to give you the words to say. Ask Jesus to fill your heart, so that when you talk, your words will be filled with love. If you say it with Christ, how can anyone speak against you?
I would also listen to the other brothers and sisters who have posted as they have posted some excellent advice. I agree with them as well.
Here are some good scriptures from the New Living Translation which speak moreso in our modern day language:
Matthew 7:2 (NLT)
For others will treat you as you treat them. Whatever measure you use in judging others, it will be used to measure how you are judged.
Matthew 12:35 (NLT)
A good person produces good words from a good heart, and an evil person produces evil words from an evil heart.
Proverbs 11:13 (NLT)
A gossip goes around revealing secrets, but those who are trustworthy can keep a confidence.
Proverbs 20:19 (NLT)
A gossip tells secrets, so don't hang around with someone who talks too much.
Proverbs 26:20 (NLT)
Fire goes out for lack of fuel, and quarrels disappear when gossip stops.
Proverbs 26:18-19 (NLT)
18 Just as damaging as a mad man shooting a lethal weapon 19 is someone who lies to a friend and then says, "I was only joking."
Romans 1:29 (NLT)
Their lives became full of every kind of wickedness, sin, greed, hate, envy, murder, fighting, deception, malicious behavior, and gossip.
James 4:11 (NLT)
11 Don't speak evil against each other, my dear brothers and sisters. If you criticize each other and condemn each other, then you are criticizing and condemning God's law. But you are not a judge who can decide whether the law is right or wrong. Your job is to obey it.
2 Be humble and gentle. Be patient with each other, making allowance for each other's faults because of your love.
I think, Proverbs 18:8 is said best in the King James version of the bible:
Proverbs 18:8 (KJ)
The words of a talebearer are as wounds, and they go down into the innermost parts of the belly.
However, I think the way it's said in the Message is a bit funny, but it gets the point:
Proverbs 18:8 (The Message)
Listening to gossip is like eating cheap candy; do you really want junk like that in your belly?
I especially like Proverbs 11:13, because it talks about the importance of trust in friendship.
Jesus said that we should love one another. An important part of love is trust. Often times, our closest friends are those we trust most. We trust them enough to share our secrets with them. We trust them to keep our secrets in confidence. This kind of closeness is called intimacy. God appreciates intimacy. He tells us we should pray in private.
Gossip is not loving at all. It destroys friendships and hurts people. Just think of when you have heard someone speak badly about you. It hurts deep down, like wounds in the stomach. Basically, listening to gossip makes you sick to your stomach.
I will pray for you my brother. I know it's not an easy thing.