How do you know when someone is not listening?

You can often tell someone is not listening if they exhibit distracted body language, such as looking at their phone, avoiding eye contact, or fidgeting. They may also give delayed or irrelevant responses that don't align with what you've said. Additionally, if they frequently interrupt or change the subject, it can indicate a lack of engagement. Overall, a lack of focus and connection in the conversation are clear signs of disinterest.