Could anyone elucidate the reason why 'laborious' is the right way of spelling and not 'labourious'? After all 'labour' is the correctly spelt word and despite of it 'labourious' is not the right one. Is it any rule that can justify it?


Shortly after the United States won its freedom from England, Noah Webster wrote the first dictionary of American English, distinguishing it from British English “Language is the expression of ideas; and if the people of one country cannot preserve an identity of ideas, they cannot retain an identity of language.”

Webster reformed the spelling in his dictionary, simplifying what he thought were arcane rules. He changed the –ce in words like defence, offence, and pretence to –se; abandoned the second, silent "l" in verbs such as travel and cancel when forming the past tense; dropped the "u" from words such as humour, labour and colour; and dropped the "k" from words such as publick and musick.

In American English, it is labor and laborious.

lukandIs it there any rule that can justify it?

Probably not, but in general, words that end in 'our' (labour, colour, flavour) in British English change the 'our' to 'or' when certain suffixes are added. It doesn't always work that way, so it's hard to call it a "rule".


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My understanding was always that this is because of the 'ou...iou' which simply seemed unnecessarily vowel-heavy.

Goodness knows if this is the 'right answer'...

 AlpheccaStars's reply was promoted to an answer.

Which begs the question, Alphecca, why the UK spelling is similar to the American spelling when the suffix is added... Do you reckon it's what I was told as a student, and that it's just unwieldy, or was the original English spelling 'labourious' and changed to mimic the simplicity of the American version?

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See the last paragraph on Fowler.


English spelling reform has a long and storied history. Many have tried and partially succeeded or totally failed to make spelling more phonetic.


 CalifJim's reply was promoted to an answer.

Nobody said English spelling is logical.

So far, nobody has been able to explain to me why there's a u in four and fourteen, but not in forty.

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In this case there is a change in pronunciation. This might be a clue in the labour/laborious question. Labour has the stress on the first syllable whereas laborious has the stress on the "or" syllable. British "labour" can sound like "lay bur" whereas the American sounds like "lay bor" to me. Just stirring.

My theory is that British "labour" sounds like "LAYbur" whereas "laborious" is pronounced "layBOREious" with an "o" sound. American "labor" has a sound like the conjunction "or" (to my ear).

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