Summarize the following:
It can often be easy to slide back into kid-oriented instruction styles during swimming lessons with adults. But remember that your adult students may already be anxious or uncomfortable. The last thing they need is to be treated like a child on top of everything else.  Praise them when they deserve it, kindly explain how they can improve what they're doing, and always address them with respect and consideration. Give your students time to understand, to ask questions, and to learn at their own pace. Each student learns differently and reacts to various teaching styles differently. Observe your students and see how they seem to learn the best. Then, tailor your instruction to fit each student. For example, some learn by watching someone else do the thing, while others learn by doing and receiving feedback. Don't focus on what the adult swimmer is doing wrong. Instead, encourage them by telling them what they are doing right and providing tips on how to improve what they are already doing. If the student is struggling with a particular stroke, try saying something like, “Your side-to-side head motions are great! Now let's focus on trying to keep your arms straight all the way through the stroke.”

Summary:
Speak to them like adults. Adjust your teaching style. Stay positive.