The first is an issue: can only be looking at one thing at a time. The second doesn't seem to come up much in practice. Can eat and sign at the same time unlik

The first is an issue: can only be looking at one thing at a time. The second doesn't seem to come up much in practice. Can eat and sign at the same time unlike voice. Third isn't true -- signing is more expressive because it takes advantage of space, facial expressions, and signs can be modulated to adjust the meaning. But it almost has to be since the symbol rate is lower than speech.