Information Research Weblog

No, not the body part, the punctuation mark. It has always puzzled me why practice in the USA is to use a capital letter after the colon, which is not a full stop. British and, I think, International English, practice is to use a capital letter only after a full stop, although I believe that Oxford University Press also allow capitals if the colon introduces a list. Information Research (I say this for the benefit of future authors) allows a capital letter only after the full stop. One colleague told me that he had been told, in all seriousness, that it was because the colon was two full stops, one on top of the other, and therefore stronger!

Where did the US practice come from? My thoughts on this were prompted by a link from The Scout Report to Bartleby.com which is home to various editions of works on English usage.

So, I checked on US works, and we find that the Columbia Guide to Standard American English (1993) says:

This punctuation mark (:) can (1) signal a forthcoming list, as in He sold sundries: needles, thread, pins, buttons, and thimbles; (2) introduce a further amplification or a summary of what has just been said, as in After years of work, he finally had it: the championship; (3) let one clause explain another, as in He was late: his car had broken down; (4) lead into a long quotation, as in Jefferson wrote: When in the course of human events,…; and (5) do such separating tasks as these: Henry IV, Pt. I, II:iv:122; Dear Sir:; New York: Longman, 1987; and 11:15 A.M.

Only two of those use a following capital - introducing a quotation, which is fine, and introducing whatever follows 'Dear Sir:'

Strunk's 'Elements of style' (1918) says only that the colon is used to introduce a quotation

So, can anyone enlighten me as to where current practice comes from?