I found that diaeresis is used on the word, reelection in the following sentence of the article titled “Rational Irrationality” in the New Yorker magazine (April 27).
“This morning’s news that economic growth slowed markedly between January and March is an unmitigated bad for Obama and an unmitigated good for Romney. The President’s reëlection chances largely hinge on being able to point to evidence that the economy is finally improving.”
As I don’t think I’ve come across diaeresises being used in the articles of today's journals so often (Correct me if I’m wrong), I checked dictionaries at hand and online.
Cambridge Dictionary online resisters reelection without hyphen nor diaeresis on ‘ee’, same as Merriam Webster online.
Both Oxford Dictionary online and Oxford Advance English Learners’ Dictionary register ‘re-election’ with the former coming with the notation - Spell ‘re-elect’ with a hyphen after the first e. Other words beginning with re- that have a hyphen are re-educate, re-emerge, re-enact, re-enter.
New Yorker used diaeresis on ‘reelection’ as shown above, and their separate article titled “The Curse of the Diaeresis’ (April 2) stated:
“The special tool we use here at The New Yorker for punching out the two dots that we then center carefully over the second vowel in such words as “naïve” and “Laocoön” will be getting a workout this year, as the Democrats coöperate to reëlect the President.”
I find no consistency of the use and non-use of hyphen and diaeresis among Cambridge Dictionary, Oxford Dictionaries and New Yorker magazine.
What is the standard rule or custom of using, not using a hyphen and a diaeresis on the words including ‘ee’ ‘oo’ letters?