That's the conclusion of a new research, which suggests that spelling mistakes are sometimes made because people know too much.
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.
"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," Telegraph quoted Ian Brookes, the managing editor of dictionaries at Collins, as saying.