Thanks Baertram. I was hoping there was a GetString() function for this; but I've had no luck finding it. I have been looking at the wiki pages. These github pages will be a good resource too. I haven't found anything that looks like what I need.
I pulled the CURRENCY_CHANGE_REASON constants into a spreadsheet and wrote a couple of formulas to convert those names into LUA code. I think I'm stuck with an internal table