I noticed that sometimes my husband and I have miscommunications. We all do, at one time or another. Most of ours happen when discussing vehicles - particularly what he did to fix mine or what needs to be done to fix it.
I realized what the issue usually is. When you know an awful lot about a particular subject, it's not uncommon to get terms crossed, mixed up and tossed around. You don't mean to do it; what seems to happen is that your brain is thinking faster than you can speak and a tossed salad of words is the result. You know what you meant. Chances are, if you're talking to someone who know as much about the subject as you do, they know what you meant, too. In fact, they may not have heard the terminology mix-up at all - they heard what you meant to say instead of what you actually said. And this is OK, as long as both conversational parties understand the subject matter equally well.
The problem arises when an expert is attempting to explain the subject to someone who doesn't understand the subject. This happens to us a lot. An excellent example happened last night, when my husband was explaining what happened to a battery that had corroded. He first said something about the terminal, then said something about the connecting cable - and then got the two mixed up in his next sentence. If I hadn't been paying close attention, I not only wouldn't have caught it, I wouldn't have thought to ask him to back up and clarify.
Sometimes these word mix-ups cause me to get lost in the conversation, and because he didn't realize the mistake, we both get frustrated. I guess the trick to effective communication is to listen to what you're actually saying vs. what you intended to say, while you're saying it. That can be quite a trick.