This could be a hedge about the Law for the commandment about taking the name of the Lord in vain, but I think it's more a matter of respect for authority. When you go to court, you don't call the judge "Joe", or even "Mr. Doe", but "Your Honor". Similarly, when we address God we usually use a term such as "Adonai" (Lord(1)).
Then again, we might need this more than other people. The first ancestors of ours we remember haggled with God (Genesis 18). His grandson got renamed "He who fights with God". We are not the most respectful of people, in much the same way that Alaska is not the hottest place on Earth.
(1) It's actually plural, Lords, but that's probably just the same as addressing royalty.
Yes, I didn't comment on his post over there because I was uncertain, and everybody there is way more erudite than I am.
But it seems to me the prohibition on speaking the Name is part of the Jewish tradition of "setting a hedge about the Law," that is, creating lesser laws far more rigorous than the actual Levitical Law, so that if you keep them it will be impossible to get anywhere near breaking the real ones.
This is very prudent, but I'm pretty sure that much of Jesus' teaching was aimed at demolishing just that arrangement.