Simple tactic to stop private conversations -- and three alternative tactics

If you're teaching a larger group, you will find that some people tend to have extended private conversations going on. I'm not talking about just one or two quick sentences shared back and forth in whispers, probably related to the class topic. This is when two people seem to be having an extended conversation (I've seen one go on for 15 minutes) and they aren't paying any attention to you or anyone else nearby.

Even if it is not disrupting the class overall, but it's likely to be distracting to you.

Here's a simple tactic which usually ices these cold:

Continue teaching, but go stand near them for a time.

I have found that my physical presence usually quells the conversation without me saying anything about it at all.

Now if you're teaching environment doesn't give you that option, then the next thing to try is making eye contact. That may not be very effective if they're really engaged.

You can also ask them a direct question -- it's even better if you know one or both of their names. "Bill, did you have a question or an observation to share?"

A tactic that can be very effective is to stop talking, wave off questions, focus your eye contact on the conversing pair, and wait. In about 30-45 seconds even very engaged conversationalists will recognize something changed and look at you. Then say, gently, "Thank you." And continue the class.

If you use either of the latter two options, be sure to follow-up outside of class with them. Remember, they are not the enemy. You're simply trying to manage the teaching environment so everyone has the best possible opportunities to learn. It could well be that their conversation was more important than your lesson. If that's true, they just need to move out of the class area to have it, out of consideration for others.