from The Telegraph
Telegraph article on spelling problems for clever people
People can be too clever to spell
Spelling mistakes are not always down to ignorance of the English language, they are sometimes made because people know too much.
By Jessica Salter
Researchers at Collins Dictionaries found that the most commonly misspelt word was supersede - being wrong on one in ten occasions.
The problem arises because people use their knowledge of the words that have a phonetically similar ending, like intercede, precede or cede, from the Latin cedere - to yield.
They then wrongly assume that supersede is spelt with a 'c'.
The less scholarly can still slip up if they base their spelling on words that are similar. Many are tempted to spell liquefy as liquify, simply because they know the correct spelling of liquid or inoculate with a double 'n' because they know how to spell innocuous.
Another common reason for misspelling is where words are spelt differently from their pronunciation. The top five misspelt words in this category are conscience, indict, foreign, mortgage and phlegm.
Researchers at Collins compiled their list of misspelt words by using a software program designed to pick up spelling mistakes to go through thousands of documents on the internet, including published books, articles and blogs.
Ian Brookes, the managing editor of dictionaries at Collins, said: "The real spelling problems occur when people have learnt the rules or have a bit of knowledge, but then make mistakes in how they apply this."
Earlier this month a university lecturer drew up a list of commonly misspelt words that he thought should be included as "variant spellings".
Dr Ken Smith from Buckingham University said misspelt words such as 'thier', 'arguement', 'ignor' and 'speach' should also be accepted alternatives to current spellings.