The differences between American-English and British-English when writing your thesis

When you are writing your thesis, one of the first things you have to decide is what style of English you will use. The most common options are American, British, or Australian English. Although they follow many of the same rules, they also have some important differences – especially in relation to spelling. This article will help you make spelling choices that match the English you are using.

Why is it so complicated?

After winning their independence from the British, Americans used language as a way to create their own identity. This led to many variations in spelling and punctuation, among other things. Australia also developed its own written conventions, which lie somewhere in between those of the US and UK (although they tend to be more British). Of the three, Australian English is generally the most flexible.

Basic spelling differences

The following “cheat sheet” outlines the preferred spelling of some words that are commonly used in academic writing.


US UK Australia
analyze analyse analyse
apologize apologise apologise
capitalize capitalise capitalise
categorize categorise categorise
characterize characterise characterise
colonize colonise colonise
endeavor endeavour endeavour
enroll enrol enroll
fulfill fulfil fulfil
globalize globalise globalise
honor honour honour
hypothesize hypothesise hyphothesise
inquire enquire enquire
install instal install
legalize legalise legalise
maneuver manoeuvre manoeuvre
maximize maximise maximise
minimize minimise minimise
mold mould mould
neutralize neutralise neutralise
optimize optimise optimise
paralyze paralyse paralyse
plow plough plough
practice practise practise
privatize privatise privatise
randomize randomise randomise
realize realise realise
recognize recognise recognise

Past verb forms

US UK Australia
canceled cancelled cancelled
channeled channelled channelled
labeled labelled labelled
modeled modelled modelled
traveled travelled travelled


US UK Australia
acknowledgment acknowledgement (either)
aluminum aluminium aluminium
artifact artefact artefact
behavior behaviour behaviour
caliber calibre calibre
center centre centre
color colour colour
cooperation co-operation (either)
councilor councillor councilor
counselor counsellor counselor
defense defence defence
estrogen oestrogen oestrogen
fetus foetus foetus
fiber fibre fibre
flavour flavour flavour
humor humour humour
judgment judgement judgement
labor labour labour
leukemia leukaemia leukaemia
license licence licence
litre litre litre
meter metre metre
neighbor neighbour neighbour
organization (either) organisation
paleontology palaeontology palaeontology
program programme 
(but program if computer-related)
sulfur sulphur sulphur
theater theatre theatre
tire tyre tyre
vapor vapour vapour


US UK Australia
aging ageing ageing
favorite favourite favourite
gray grey grey
livable liveable livable
movable moveable moveable
orthopedic orthopaedic orthopaedic
salable saleable saleable
skeptical sceptical sceptical
somber sombre sombre

Don’t forget: Consistency is key!

Each word should of course be spelled the same throughout your document. However, it’s also important not to use a mix of English styles.

 The defense minister first travelled to China in 2013. (US English/UK English)
 The defense minister first traveled to China in 2013. (all US English)
 The defence minister first travelled to China in 2013. (all UK English)

In addition, the same spelling should generally be used for all forms of a word.

The organization is headquartered in Osaka, but it usually organizes workshops in Tokyo. (all US English)
The colours of the samples varied greatly, but smallest sample was the most colourful. (all UK English)

Which type of English should I choose?

Some universities have a preference, so you may wish to check your school’s website for guidance. If you are free to decide yourself, it’s best to pick the style that feels most natural to you. Once you have done so, make sure that this is the language that is set for your document (in Microsoft Word, select Tools à Language).

Further understanding the differences

If you want to know more about spelling and other grammatical differences between these styles of English, the below tables provide more details. Bear in mind that the rules are not always very firm: there are many exceptions, and conventions are always changing!

Spelling: As can be seen, the variation usually relates to just one or two letters.

# USUKAustralia
a uses -ize, -yze (e.g. quantize, analyze)prefers -ise-yse (e.g.quantise, analyse),
but is flexible
almost always uses ise, yse
b -er (e.g. center, meter, etc.)-re (e.g. centre, metre, etc.) British usage
c uses -or (e.g. honor, color, splendor)uses -our (e.g. honour, colour, splendour) British usage
d uses –ction (e.g. connection)acceptable to use –xion (e.g. connexion)American usage
e prefers single consonants 
(e.g. canceled, focuses, appal),
with certain exceptions for words
in which the stressed syllable falls on the doubled consonant (e.g. willful)
uses double consonants
(e.g. focusses,cancelled, appall),
with certain exceptions (e.g. wilful)
British usage
f often drops -e for word modifications (e.g. judge àjudgment, live à livable)generally keeps e for word modifications (e.g. judge à judgementlive à liveable)keeps -e: (e.g.judgement), like British;
but sometimes drops -e: (e.g. livable)
g -e usually preferred to -oe or -ae (e.g.pediatricianleukemia, etc.)-oe and -ae used
(e.g. paediatrician, leukaemia, etc.)
British usage

Punctuation:  Here the main differences relate to whether to use single or double quotation marks, and where to put other punctuation in relation to those quotation marks.

# USUKAustralia
a Double quotation marks (“x”), but alternate with single for quotations within quotations (e.g. She said, “This model has been called ‘the best.’”)Single quotation marks (‘x’), but alternate with double for quotations within quotations (e.g. She said, ‘This model has been called “the best”’.)UK usage
b Punctuation appears within quotation marks (e.g. “The best there is,” she said. or She said, “the best there is.”) except when punctuation emphasizes the writer’s sentence rather than the speaker’s quotation (e.g. Did she say, “the best there is”? or “She told them we are “the best there is”!)Punctuation appears outside quotation marks, except when the punctuation is part of the original quotation (e.g. ‘The best there is’, she said. but She said, ‘the best there is.’; also, Did she say, the best there is’? but She asked, ‘the best there is?’)UK usage

Verb forms:  The different styles of English do not always agree about whether singular or plural verbs should be used with certain nouns. There is also disagreement about some past forms of verbs.

# USUKAustralia
a Collective nouns (nouns referring
to a group of individual things)
take verbs as conjugated for
singular nouns
(e.g. The team is
going to win. or 
The staff has decided. or
The team leads the charge.)
Collective nouns (nouns referring
to a group of individual things)
take verbs as conjugated for plural nouns
(e.g. The team are going to
win. or The staff have decided.
or The team lead the charge.)
US usage
b Verbs take -ed endings
for simple past tense and
past participles
(e.g. compel àcompelled,spell
à spelled, learn à learned)
with the exception of
common irregular verbs
(e.g. take à took, hear à heard)
Verbs take -ed endings for simple
past tense and past participles,
but with more exceptions
(e.g.compel à compelled but spellà
spelt,learn à learnt); irregular verbs are
conjugated the same
UK usage

Abbreviations:  There is also disagreement over how to use periods in abbreviations.

US UK Australia
Most title abbreviations take a period
(e.g. Doctor à Dr. Missus à Mrs. Honorable à Hon. Avenue à Ave.)
Title abbreviations take a period only if the abbreviation does not end on the last letter of the full word
(e.g. Doctorà Dr Missus à Mrs but Honourable à Hon. Avenue à Ave.)
UK usage


Khin Aung Htun
17 March 2020

If someone is writing his or her document in British style of English, but he or she would like to cite some reference articles in the document. These articles were written in American English. Should be or she change the writing style for these articles or keep the original style?

Kalite Akademik Tercüme
17 March 2020

As you know, citations/references are expressions specially worded by the author of the original text; therefore, the original form should be followed. For more information, please refer to “APA Style Book – Publication Manual of the American Psychological Association, Chapter 6.

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