Below, for illustration purposes only, you can find the typology of some of the main differences in spelling between British English (including Oxford spelling, with its variants) and American English.

Main spelling differences between British English and American English

 

British English

Oxford spelling

American English

British words ending in -re > -er

centre, fibre, litre, theatre...

center, fiber, liter, theater...

British words ending in -our > -or

colour, honour, flavour, humour, labour, neighbour...

color, honor, flavor, humor, labor, neighbor...

British words ending in -ise or -ize (and            -isation or -ization)

realise, organise, recognise, globalise, specialise...

 

specialisation, globalisation...

 

realize, organize, recognize, globalize, specialize...

 

specialization, globalization...

 

realize, organize, recognize, globalize, specialize...

 

specialization, globalization...

 

British words ending in -yse > -yze

analyse, paralyse, catalyse...

analyze, paralyze, catalyze...

British words ending in -ogue > -og /-ogue

catalogue, analogue, dialogue...

catalog/catalogue, analog/analogue, dialog/dialogue...

British words ending in -ence > -ense

defence, licence, offence...

defense, license, offense...