Last week, I posted a few notes about how the alienness of aliens might make it hard to learn to communicate with them ("Alien Encounters", 9/15/2016). To start with, even the basic modes of signal generation and interpretation would probably not fit our biology very well. And the interpretation of signals — biological as well as cultural — might also be outside the range that we expect from experience with our fellow humans.
Some people, including my colleague and friend Victor Mair, nevertheless proposed methods based on those that have been found to work in human contexts. So to clarify the issues I was trying to raise, here's a little Alien Encounter Sketch.