Usage and Grammar

A. I don’t see much difference. But I would suppose that “would” is more polite, because it expresses the idea of probability, and of willingness, and of the desire that something be done, whereas “could” is more in the realm of ability (yes I can).

And according to the American Heritage Dictionary, “would” is used to make a polite request. But then again, a similar thing is said about “could”: “Used to indicate tentativeness or politeness. I could be wrong. Could you come over here?”

Now, as far as I’m concerned, it becomes then a matter of context and tone. Look at the difference between these two sentences, for example:

Would you do me a favor?

Would you please just shut up.

And even “will” could be used interchangeably with “would” or “could.”

Perhaps “could” and “would” are just both vying for what is a sort of awkward subjunctive mood, trying to put a command into the mode of the hypothetical, to increase the possibilities of expression—toward either politeness or irony (e.g., changing the tenor of “Please close the door”).

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]

A. In my opinion, sans cannot be “archaic”: it is the modern French word for “without,” as I’m sure you know. More than fifty million French people use it every single day, and though some may say French culture and therefore language is passé, the French would disagree. As for whether “sans” is affected in English, that’s certainly a matter of personal style. Some would say that any attempt to use French within English is affected (her hair is the color du jour; I’m applying a sort of faux finish to this wall). But CMOS, as far as I know, tends not to pass judgment on rhetorical idiosyncrasies, at least those that do not introduce a lack of clarity.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]