Laziness is all well and good, but when you start to change the outside world in order to make your code simpler, then you're heading for problems. Forcing users to undestand 'R' to mean 'Th' is a case in point.
The point of programming is to encapsulate the complexity in our own code (where we know(?) that we can handle it), rather than downloading it on users. That way one person (the coder) is inconvenienced, rather than the entire user community.
Here endeth the pontification