This website I found converts text into MIDI files, which is in morse code.
Because It is MIDI, you can put it as your ringtone as well.
I could imagine writing down something horrible, then be caught by your buddy who juuust so happened to have worked in signals 
http://www.planetofnoise.com/midi/morse2mid.php
Just tried it, it does no accented letters and only very basic punctuation, ie . , / + ?
It can handle Chinese though.