Oxford spelling uses the spelling that is closest to a word’s etymological origin. For example, we spell the word ‘organization’ with a z because the Medieval Latin word from which it derived had a z. We spell the verb ‘to analyse’ with an s because the Greek root had an s. We spell the word ‘centre’ like in the French word centre.
Another way is think about Oxford spelling is that its foundation is built with British spelling with sprinklings of American spelling. Using Oxford spelling, we spell the word ‘travellor’ with two l’s as in British spelling, and not with one l as in American spelling. Also using Oxford spelling, we spell the word ‘organization’ like Americans do.
American spelling, as created by Noah Webster, focuses on pronunciation. For example, there is a /z/ sound in the word ‘analyse’, which is the reason for which Americans spell it with a z, yet we spell it with an s in Oxford spelling.
With English being the lingua franca of our times, the spelling in English cannot be adequately reformed with respect to pronunciation without prejudice due to the many different varieties of English throughout the world.
For example, the sound represented by the letter o in the word ‘record’ is pronounced differently by Americans and by the British. So with a more strict spelling that has a one-to-one correspondence between a letter or a combination of letters to a sound, Americans and the British should spell the word differently due to the difference in their pronunciation of the word. However, spelling ‘record’ and other words this way would make English writing more inaccessible to an international audience. This is not even touching upon the varieties of English that exist within an Anglophone country. Also, whose pronunciation should we use as a standard if such a reform of English spelling should occur?
Writing for an international audience, I use Oxford spelling. I am in good company, as international organizations such as the UN, the ISO, the Oxford University Press, and the Oxford English Dictionary uses it.
Once more people use Oxford spelling and it becomes a standard in more organizations, English spelling will become more accessible to a larger audience instead of adhering to multiple national standards.