Although vs. Though

Some editors, for some reason, tend to try to change each though I use into an although. I don’t get it — both are fully standard, both are commonplace in edited legal prose, and have been for centuries. A quick Lexis NEWS;US database search reveals that “although” and “though” are roughly equally common today; and “though” is no newcomer, at least according to Google Ngrams, which reports that “though” was actually even more common in English-language books in the past.

Why change an author’s “though” into “although”? The only explanation that I can see is that some people think “though” is some sort of new and not-fully-standard shortening of “although.” But if that’s their belief, it’s an incorrect one: Both words have been used since the time of Middle English, and, as I’ve noted, “though” is used routinely in standard published prose. And while I agree that legal writing shouldn’t be informal to the point of being unprofessional (you won’t find any OMGs or ROTFLs in my articles), “though” is hardly slang or otherwise unusually casual.