Common Americanisms

Posted on 20 March 2015 by Emily Stella

The battle between UK and US English

We correspond with people in English across the globe every single working day – and, without realising it, many of us write in a mix of US and UK English.

But are you aware of it?

If you work for a global company, they may want you to write in US English over UK English, so be sure to check your own company standards. Whichever English you’re writing in, the most important thing is to remain consistent throughout your document.

Here are the most common differences to watch out for.


Contrary to popular belief, z is not an Americanism. It was standard in UK English until the 20th century, when s became more common. The Oxford English Dictionary and the Oxford University Press still use z.

However, most UK publishers and writing authorities prefer s, and there are instances where only -ise is correct.

In the UK, we realised the need to stabilise the situation.

In the US, we incentivize investors by capitalizing assets.

Common verbs where only -ise is correct (in UK and US English): advertise, advise, apprise, chastise, comprise, compromise, despise, devise, disguise, excise, exercise, improvise, incise, prise, promise, revise, supervise, surmise, surprise, televise.


For documents in UK English, write -yse.

-yze is exclusive to US English.

analyse (UK) > analyze (US)

catalyse (UK) > catalyze (US)


Serial comma (or Oxford comma)

In US English, it is common practice to include a comma before and and or at the end of a list. This is known as a serial comma or Oxford comma:

Your writing is clear, concise, and professional.

We support the environment, fair trade, and community responsibility.

We protect consumers, enhance the integrity of the financial system and its organisations, and promote effective competition.

In UK English, the serial comma is only used if it adds clarity to the list (as in the last example above).

Quotation marks with commas and periods

UK English

In UK English, commas and full stops sit outside closing quotation marks unless part of the quoted material:

The client asked us to explain the ‘key findings from the report’.

All I heard was James telling the CEO to ‘get lost’.

US English

In US English, commas and full stops sit inside closing quotation marks, even if they are not part of the quoted material:

The client asked us to explain the ‘key findings from the report.’

All I heard was James telling the CEO to ‘get lost.’


Burnt, dreamt, learnt, spelt

Is it learned or learnt? Spelled or spelt?

Most regular verbs form their past tense by adding -ed. Some verbs, such as burn, dream, learn and spell can be spelt with a -t ending or an -ed ending. For these verbs, it’s more common to use -t in UK English and -ed in US English.

It’s worth noting that the past tense of earn is always earned, even in UK English.

Centre or Center?

This is a simple spelling difference, but one to watch out for.

Words ending -re is the UK spelling – theatre, calibre, litre, manoeuvre.

And words ending -er is the US spelling – theater, caliber, liter, maneuver (also note the lack of an o).

Similarly, words ending in -our is the UK spelling – colour, flavour, humour, labour.

And words ending in -or is the US spelling – color, flavour, humor, labor.

Single or double l

In UK English, words ending in a single l often need a double when extended; words ending in double l lose the second one.

In US English, words tend to keep the same number of l’s when you extend them.

Label > Labelled (UK) > Labeled (US)

Model > Modelled (UK) > Modeled (US)

Jewel > Jewellery (UK) > Jewelry (US)

And, though obvious, make sure your language settings on Microsoft Office are English (United Kingdom)!