American English vs. British English in Research Manuscripts: A Free Guide

This free guide provides an overview of the most common spelling differences in research papers when choosing American English or British English.

In a simpler world, English would be written the same way everywhere. However, when Noah Webster set out to create an American English dictionary in the early 1800s, he did more than just add new words to British English: he also revised the spelling of many common words to eliminate what he saw as unnecessary letters. His new spellings were adopted in the US but not the UK, and these spelling differences remain to this day.

American English vs. British English - AJE The list below is intended to provide an overview of the most common spelling differences between British and American English. The words beginning each list are intended to establish overall patterns, whereas the words in italics towards the end of the lists are examples of deviations from the rule. Remember that you can choose between “English (U.S.)” and “English (U.K.)” in Microsoft Word when setting the language for your document. This change allows the spell check to help catch these differences in spelling.

Click here to download a list of American English and British English spelling differences for future reference.

-ize (-yze)/-ise

AmericanBritish
characterizecharacterise
prioritizeprioritise
specializespecialise
analyzeanalyse
catalyzecatalyse
sizesize
exerciseexercise
The products of the catalyzed reaction were characterized using specialized equipment.The products of the catalysed reaction were characterised using specialised equipment.

-or/-our

AmericanBritish
behaviorbehaviour
colorcolour
favorfavour
contourcontour
Because of its decolorization behavior, this material is favored.Because of its decolourisation behaviour, this material is favoured.

-er/-re

AmericanBritish
centercentre
fiberfibre
literlitre
parameterparameter
Five milliliters of the mixture containing the fibers was pipetted on the center of the slide.Five millilitres of the mixture containing the fibres was pipetted on the centre of the slide.

e/(ae or oe)

AmericanBritish
amebaamoeba
anesthesiaanaesthesia
diarrheadiarrhoea
leukemialeukaemia
cesiumcaesium
The leukemia patient was given anesthesia before the procedure.The leukaemia patient was given anaesthesia before the procedure.

-se/-ce

AmericanBritish
defensedefence
practice (noun and verb)practice (noun)/practise (verb)
license (noun and verb)licence (noun)/license (verb)
defensivedefensive
advice (noun)/advise (verb)advice (noun)/advise (verb)
The defense attorney had practiced law for over thirty years.The defence attorney had practised law for over thirty years.

-/e, -og/-ogue

AmericanBritish
agingageing
acknowledgmentacknowledgement
judgmentjudgement
analoganalogue
dialogdialogue
dying/dyeing (from die/dye)dying/dyeing (from die/dye)
The aging analog-to-digital converter is slowly dying.The ageing analogue-to-digital converter is slowly dying.

-l/-ll OR -ll/-l

AmericanBritish
fulfillfulfil
enrollenrol
skill, skillfulskill, skilful
labeledlabelled
signalingsignalling
propelledpropelled
revealingrevealing
The skillful student noted that the drop in enrollment may be signaling a problem with the study design.The skilful student noted that the drop in enrolment may be signalling a problem with the study design.

This list of differences between American English and British English is by no means exhaustive, but we hope that it helps give you an idea of the distinctions between the two styles of writing. If you have questions about any particular word, please contact us.

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