I think we use "don't" and "can't" almost exclusively in normal conversation here in the U.S. "Do not" and "cannot" are reserved for making special emphasis or dramatic effect. But we have a long history of using the word "don't" — particularly in admonishing our former colonial masters. Have a look at this colonial American flag (Gadsden Flag, source: Wikipedia).

![yellow "don't tread on me" flag with snake][1]


 And its naval equivalent:

![red and white striped "don't tread on me" flag with red and yellow snake][2]


  [1]: https://i.sstatic.net/839Fp.png
  [2]: https://i.sstatic.net/x8lc4.png