Some words have more than one correct spelling. American, British, Australian and Canadian English all have their own preferences. Even within those, there can be multiple spellings. For example, in the UK 'realise' is often preferred. However, 'realize' has been used in British English for centuries and is preferred in the Oxford English Dictionary. However, no matter which spelling is preferred, one thing is always wrong: you mustn't use two different spellings in the same document.
We used PerfectIt, Intelligent Editing's add-in for MS Word that finds inconsistencies, to check 1200 randomly selected documents. Each document was 1500 words or more and was downloaded from the internet. The results were staggering. Everyone knows not to use two different spellings for the same word, but we found that more than a quarter of documents published online did exactly that.
The worst offender was 'organise' and 'organize', which came up in more than 10% of all documents (including all the sub-variations, such as 'organization' and 'organizes'). But it was far from the only one. Here's the full top 10.
|RANK||WORD||FREQUENCY (% OF DOCUMENTS)|
|1||organise / organize||12.4%|
|2||centre / center||6.5%|
|3||focussed / focused||3.0%|
|4||recognise / recognize||3.0%|
|5||analyse / analyze||1.7%|
|6||advisor / adviser||1.5%|
|7||learnt / learned||1.4%|
|8||finalise / finalize||1.2%|
|9||emphasise / emphasize||1.1%|
|10||labour / labor||1.0%|
PerfectIt clearly found mistakes that spelling and grammar checkers were missing. However, like any software, you can't just assume that every result means the document is wrong. For example, names can be intentionally inconsistent. In the UK, 'centre' may be preferred, but you'd still use 'center' in the name 'Centers for Disease Control and Prevention'. The same is true for 'organisation'. It's less common, but 'learned' and 'learnt' can also be used in the same document. They can even both be used in the same sentence: 'he learnt from the learned professor' where (unless your name is Homer Simpson) 'learned' is pronounced with two syllables.
For this reason, a number of words weren't included in our analysis. These include 'programme' and 'program', because in the UK both are used but 'program' is reserved for software. Similarly, 'cheque' and 'check' may be an inconsistent spelling. However, since 'check' is also a verb, consideration of context makes it inappropriate for review with software. Other examples are tire/tyre, license/licence, curb/kerb, metre/meter, and practice/practise.
Inconsistent spellings don't just happen, they happen a lot. Our finding that more than a quarter of documents over 1500 words contain an inconsistent spelling is staggering. The worst document we found had 17 different words spelled inconsistently. When you're writing, you need to choose one style and stick to it. When you're editing, watch for inconsistent spellings, especially if more than one author has helped to put a document together.
The Top 10 gives you a starting point for words to keep your eye on. However, there were 100 more words that came up in our research and when you're going through text, you need to consider all of them. PerfectIt can help you present your documents at their best by automatically locating inconsistencies that would otherwise pass you by. However, it's important to keep your eyes peeled and pay close attention to an error that's surprisingly frequent.