When peers or collaborators do not understand you, do not blame it on them (it’s counterproductive). Either you have not communicated clearly enough or they have insufficient background to understand. Take credit for the miscommunication and try a different approach. Be prepared to educate.
First, identify points of comprehension. What parts did he or she understand? Use comprehension as an anchor for the rest of your revised approach. From there, tackle the incongruities. Teach concepts, use metaphors, whatever it takes to spread the butter across the bread. Repeat yourself if you need to. Repeat yourself if you need to.
Some people simply refuse to listen. It is still your fault – for not claiming attention and for choosing to speak in the first place. Know your audience. Only then will you be able to connect.
Be patient. Take responsibility. What is the point of communicating if you are not understood?