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

American British
characterize characterise
prioritize prioritise
specialize specialise
analyze analyse
catalyze catalyse
size size
exercise exercise
The products of the catalyzed reaction were characterized using specialized equipment. The products of the catalysed reaction were characterised using specialised equipment.

-or/-our

American British
behavior behaviour
color colour
favor favour
contour contour
Because of its decolorization behavior, this material is favored. Because of its decolourisation behaviour, this material is favoured.

-er/-re

American British
center centre
fiber fibre
liter litre
parameter parameter
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)

American British
ameba amoeba
anesthesia anaesthesia
diarrhea diarrhoea
leukemia leukaemia
cesium caesium
The leukemia patient was given anesthesia before the procedure. The leukaemia patient was given anaesthesia before the procedure.

-se/-ce

American British
defense defence
practice (noun and verb) practice (noun)/practise (verb)
license (noun and verb) licence (noun)/license (verb)
defensive defensive
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

American British
aging ageing
acknowledgment acknowledgement
judgment judgement
analog analogue
dialog dialogue
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

American British
fulfill fulfil
enroll enrol
skill, skillful skill, skilful
labeled labelled
signaling signalling
propelled propelled
revealing revealing
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.

Share with your colleagues

Share your work as a preprint and help move science forward

We invite you to share your research with the community by posting it online as a preprint. Our sister company, Research Square, is a trusted preprint platform that lets you get credit for your unpublished research early, increase your citations, and get feedback from the community.

Related Articles

Active vs. Passive voice: What’s the difference? What should I use? And why does it matter?

Manuscript Formatting Consistency

Editing Tip: Style Guides

Here are links to some style guides commonly used for academic writing. Read More »

Maintaining Consistency in Academic Writing and Research Manuscripts: A Free Checklist

Manuscript Formatting Consistency

Maintaining Consistency in Academic Writing and Research Manuscripts: A Free Checklist

Use our handy checklist to make sure your next research manuscript is free of inconsistencies that can annoy reviewers and readers. Read More »

Stay up to date

Sign up for early access to AJE Scholar articles, discounts on AJE services, and more