What is a one-sentence summary of the following article?
A common early sign someone is becoming tense is clenching the jaw tightly. Most people don't realize when they are doing it, so it's a great way for you to gauge how well your opinion is being received. If you start to see jaws tighten, dial back your rhetoric or pause so the other person can address the source of the tension. If you start to notice you are the one becoming tense, relax your jaw. Remind yourself this is just a conversation, and there is no need to get worked up. As people get worked up, their volume tends to get progressively louder. The raised voices are usually a response to frustration from feeling like they aren't being understood. In fact, many people describe the feeling of not being understood as not being heard or not being listened to. To reduce some of the tension, bring the conversation back down to an appropriate volume. To do this you just have to lower your speaking volume. The other will naturally start to match your tone. If you notice you are the one who is escalating the volume, an effective way to immediately deescalate is to comment, "Wow, I am talking really loudly; I need to bring it down a notch." This will reset the conversation to a reasonable tone and acknowledge things were getting a little heated. Look for increased or exaggerated expressions. Pacing, leg shaking, fist clinching, large hand movements, and foot tapping can all be signs of agitation. You'll know the person you are speaking to is not happy with your opinion as the behaviors increase or become more intense.You should take this as a sign to back off. This is a good time to do some listening. Letting to the other person talk and helping them feel understood will dissipate the tension. Another sign the conversation is getting tense is the type of language used. If you notice the communication becoming progressively more aggressive or sarcastic, it might be time to take a break. It's difficult to dial back a conversation that has reached this stage, so consider changing the topic. You can then reintroduce the subject of disagreement, when cooler heads prevail. Avoid using sarcasm and aggressive language on your part.This will only make any perceived offense worse.

Summary:
Look for clenched jaws and teeth grinding. Check the volume. Measure the level of animation. Monitor the tone of the conversation.