Do not read this until you have done the practice dictation in Week 3.
British and American Spelling
There are several areas in which British and American spelling are different. These differences often come about because British English has tended to keep the spelling of words it has absorbed from other languages, such as French, while American English has adapted the spelling to reflect the way that the words actually sound when they're spoken.
If you're writing for British readers, you should only use British spellings. In some cases, the American spellings are acceptable in British English as well. Above all, it’s important to stick to one style or the other throughout the same piece of writing.