It never ceases to amaze me that, while my brain has no difficulty coming up with the spelling of “hors d’oeuvre”, I have to look up the word “broccoli” on a regular basis to remind myself that it has two c’s and only one “L” and not the other way around. Have you noticed any words that give you such pause?
I decided to capitalize the “L” in the above sentence in order to make it crystal clear that the letter is an “L” and not a one or an “I”, and also to set it off in quotation marks to help the brain read it as intended. I think that “L” is the only letter in the Arabic alphabet likely to be confused with another symbol when typed.
As for the “c”, I believe that although in general it is not correct to use an apostrophe to signify the plural as opposed to the possessive, when one is speaking of multiples of a single letter, the use of an apostrophe is really the best choice to get the concept across, and as the plural state of the letter is then apparent, the quotation marks are no longer needed.
An apostrophe is particularly appropriate if the letter to be multiplied is “a”, since it is of itself a standalone word, to which adding an “s” without an apostrophe creates another word, “as”. As in many cases, context is also a factor to readability.
I am pleased that my daughter gets a lot of A’s on her report card.