Letter omission and letter addition are common causes of\u00a0spelling errors:\n\n \tOmitting a letter means missing it from a word.\n \tLetter addition means adding an unnecessary letter to a word.\n\nIn this post, we take a look at a few terms affected by these issues. Remember to look for similar words in your writing, as this will help you avoid mistakes.\nLetter Omission Errors\nLetter omission errors are common when a word is supposed to contain double letters. Funnily, one example of this is the word \u201cmisspell,\u201d which is often (wrongly) written as \u201cmispell.\u201d As such, you should always check whether a word needs a double letter. Other examples include:\n\n\n\n\nCorrect Spelling\n\n\nIncorrect Spelling\n\n\n\n\nBeginning\n\n\nBegining\n\n\n\n\nEmbarrass\n\n\nEmbarass\n\n\n\n\nOccurrence\n\n\nOccurence\n\n\n\n\nPossess\n\n\nPosess\n\n\n\n\nHowever, not all letter omission errors involve double-letter words. In some cases, you may miss a letter because it\u2019s silent or hard to hear when the word is pronounced. This is true of the following terms, for instance:\n\n\n\n\nCorrect Spelling\n\n\nIncorrect Spelling\n\n\n\n\nLiaise\n\n\nLiase\n\n\n\n\nKnowledge\n\n\nKnowlege\n\n\n\n\nUnfortunately\n\n\nUnfortunatly\n\n\n\n\nWhich\n\n\nWich\n\n\n\n\nThere\u2019s not, unfortunately, a simple rule for remembering these words. But it is worth learning about silent letters, as these are frequent offenders.\nLetter Addition Errors\nLetter addition often occurs when someone adds an unnecessary double letter in a word. This is particularly common when a word already contains one double letter. \u201cRecommend,\u201d for example, is often misspelled as \u201creccommend\u201d (i.e., with an extra double \u201cc\u201d). Other examples include:\n\n\n\n\nCorrect Spelling\n\n\nIncorrect Spelling\n\n\n\n\nAcross\n\n\nAccross\n\n\n\n\nDisappoint\n\n\nDissappoint\n\n\n\n\nHarass\n\n\nHarrass\n\n\n\n\nParallel\n\n\nParrallel\n\n\n\n\nLetter addition errors also affect words that do not contain a double letter. Common examples of these include:\n\n\n\n\nCorrect Spelling\n\n\nIncorrect Spelling\n\n\n\n\nCuriosity\n\n\nCuriousity\n\n\n\n\nForty\n\n\nFourty\n\n\n\n\nTruly\n\n\nTruely\n\n\n\n\nUntil\n\n\nUntill\n\n\n\n\nIn some cases, it helps to learn how spellings change when adding a suffix. The extra \u201ce\u201d in \u201ctruely,\u201d for instance, is wrong because we typically drop the final \u201ce\u201d in when adding a suffix to a word that ends in "e."\nDouble Trouble!\nSome words invite letter omission and letter addition errors at the same time. These can be particularly tricky, so make sure to double check any words you\u2019re uncertain about. Take the following, for instance:\n\n\n\n\nCorrect Spelling\n\n\nIncorrect Spelling\n\n\n\n\nBroccoli\n\n\nBrocolli\n\n\n\n\nNecessary\n\n\nNeccesary\n\n\n\n\nQuestionnaire\n\n\nQuestionairre\n\n\n\n\nTomorrow\n\n\nTommorow\n\n\n\n\nRegional Variations\nIt\u2019s also worth looking out for regional spelling differences. In terms of letter omission and addition, for example, it is worth noting that most countries outside the US double the \u201cl\u201d when adding a suffix to certain words.\n\nIn American English, for instance, we would write \u201ctravel,\u201d \u201ctraveler, and "traveling.\u201d But in British or Australian English, while "travel" is the same, the other terms would be spelled \u201ctraveller\u201d and "travelling" instead.\n\nThus, if you use a US spelling of one of these words when writing for an audience outside the US, it could look like a mistake. But one way to avoid this is to ask a proofreader to check your writing for errors.