Hm, I’ve noticed something slightly different. Instead of dropping the “al” from “historic,” I’ve noticed people adding it. I grew up hearing “historic,” and “historical” sounds redundant to me.
I haven’t noticed “biologic/al” or “radiologic/al.”
But I can’t find my Advanced Grammar textbook, so I can’t say for certain which is correct, unfortunately.
IMHO, two different situations here, probably with different explanations. I’ll tackle the one, if someone else will take care of the other…
Historic/al
There are clear, important, and valuable differences between ‘historic’ and ‘historical.’ In my mind, and in the usage as I’ve observed it, ‘historic’ is properly used to describe an event that is currently taking place, or is being described in the context of its time. ‘Historical,’ on the other hand, is most often used with regard to data or information that is being used as a reference.
Examples:
“The demolition of the Berlin Wall can only be described as historic.” Here we have a sentence that wants to tell you that a particular event – even though it’s taking place NOW – is ‘historic,’ meaning that it is recognized as a history-making happening.
“The historical findings disproved the engineer’s theory about the collapse.” Here the author is trying to describe stuff, in this case ‘data,’ that has been around for a while. The adjective is used to let us know that the past has been consulted.
Interesting and helpful posts, but I must stick to my original thesis regarding an accelerating movement away from using “al,” as described in my OP.
In recent years, I’ve heard leading scientists increasingly embrace the term “biologic weapons,” rather than “biological.”
Such as, one would not refer to an “ergonomical chair,” but instead to an “ergonomic chair.” Bordelond’s theory that the sound of the term may dictate which is used seems reasonable.
BTW, the addition of this extraneous “al” was prevalent in 18th and 19th century writing.