It is possible to ascertain whether or not people are paying attention to you, while speaking to them (either individually or as a group). Suppose, for instance, that you are talking on a complex subject: like the subject of the workings of the NJ unemployment insurance benefits scheme. Let’s even suppose that you are talking on a particular aspect of it, like that of dealing with www.njuifile.net login requirements. In that scenario, it is easy to lose your listeners along the way: hence the need for you to check, from time to time, to ascertain whether or not you are still together.
One way in which you can ascertain whether people are paying attention to you while speaking to them would be by reading their body language.
The other way in which you can ascertain whether or not people are paying attention to you while speaking to them would be by asking them the pertinent questions. These are questions they are supposed to be in a position to answer, if indeed they have been listening to you. But you shouldn’t take offence if it emerges that they are unable to answer the questions. You may be facing a situation where the people in question have been listening to you, but they lack the capacity to comprehend what you are saying.