First of all, give yourself a break, it is not rude if you don’t understand someone with a communication impairment. Don’t put yourself under pressure as this makes it harder to understand, and the conversation may become stressed and awkward.
It is really important to treat the person you’re talking to with respect and to give them your full attention. We all like to be treated kindly and those with communication impairments are no different.
Look at each other and make eye contact. Remember that communication is more than just speech. Body language, facial expression, gestures, the written word, pictures, and technology are all there to help us to understand each other.
Try not to get frustrated, don’t roll your eyes, don’t sigh, as that is rude!
The nodding dog (nodding and hoping for the best) while good intentioned, just isn’t helpful. It leaves you in the dark and it leaves the person communicating feeling unheard and perhaps disrespected. Similarly, if you think you have understood but you are not sure; just check it out with them.
Remember to consider the environment. A busy, noisy room or one with lots of distractions will make communication trickier. If possible, ask if they would like to move to a quieter location, or at least away from overhead speakers. If you are planning ahead consider this when you make your arrangements.