Ukulele
It seems strange that ukulele should feature in the 25 most commonly misspelled words in the English language -- we wonder just how much call there is for the instrument. But there it is. It is spelled with two 'u's and two 'e's, in that order.
This page was suggested by the list of "25 of the most commonly misspelled words in the English language", in the article on "spelling" in Garner, Bryan A., The Oxford Dictionary of American Usage and Style, Oxford University Press, 2000; on line at Oxford Reference Online. Oxford University Press, under licence to Hull University. 18 July 2006. <http://www.oxfordreference.com/views/ENTRY.html?subview=Main&entry=t26.e2017>. Although the list claims "25 of the most commonly misspelled words in the English language", it may reflect the American language of the book rather than AWE's experience of English teaching in Britain. Users of AWE may find more use in our categories spelling and spelling common errors.
AWE shares the confidence of the original article: "Naturally, [the commonly misspelled words] are spelled correctly here".