Don't raise your voice.
Start keeping a tally. For every time they interrupt you, they lose one minute of recess time- the entire class. (Alternatively for every interruption they're detained five minutes after school- the entire class.) Explain this to them at the beginning of class, and then without a word start keeping a tally at the top of the chalkboard. No warnings- if you're interrupted, a mark goes up. Then follow through with it and detain them. After a few times they'll get the idea.

Shouting at them only makes them tune you out. Taking away their recess and/or keeping them after school hits them where it hurts.
( The Resident Loon Not a demographic. Do not measure., Mon 11 May 2009, 18:36, 2 replies, latest was 16 years ago)

I do this
Keep a tally, they just don't get it.
They still talk.
( Mrs Entity is in hiding., Mon 11 May 2009, 19:10, Reply)

but
do you carry the punishments out?
(Shippy likes linebreaks and doesn't care what you think, Mon 11 May 2009, 19:32, Reply)

Yes indeed
We have all missed 10 minutes of a 15 minute break every day for a week. They still didn't get it.

At the end of the day I won't let them go home until the all shut up. Most days they are 10 minutes late out.
( Mrs Entity is in hiding., Mon 11 May 2009, 20:24, Reply)

The problem with that...
... is that you have to supervise their detention. The point is to punish them, not yourself.
( Enzyme is powered by sunlight, Mon 11 May 2009, 19:34, Reply)

It has to be that way sometimes.
The thing is, if you make it so unpleasant for them that they really hate it, they'll get the point. I've had to do this with my own kids- I would ground them, then stand guard over them and be so growly and terse as to make it really a lousy time. Make sure that they know that you're angry with them for making you go through it too, and stay in their faces the whole time. They'll hate it.

Again, if this is done once or twice the message will get through. It may be a drag for you, but it will work.
( The Resident Loon Not a demographic. Do not measure., Mon 11 May 2009, 20:06, Reply)