Why does Answers.com spell certain words the English way?
Why not? There are several Englishes, and there are at least two standard Englishes: British English and US English. There are some differences in spelling and usage, but all in all not that many. Neither spelling of divergent words is incorrect.
Most differences between British and US English would be, I believe, in the more localized idioms or in casual language. When writing in the best standard or 'business' English of either variety, it would be very difficult to find language that would be confusing or misleading to reasonably well educated speakers of English.
However, for the sake of clarity and consistency, it is the official position of Answers.com's Q&A community that questions and answers be written in standard American (US) English.
Spelling in American English is a little different from spelling in British English; both are English. In addition, many people who can speak a language fluently do not necessarily know how to spell words in that language, yet they still "use" that language. For example, a little child "uses" English but probably cannot spell the words that he or she "uses."
To learn how to spell words, sound out the letters. Look in a dictionary for the pronunciation and meaning. Learn the patterns of how to spell English words, for example, how to add -ing or -ed to words. Pay attention to words that 'break the usual rules'. Lastly, practice. Spell the word out loud, write it, speak it in a sentence. It takes time to learn any subject, but you'll do it !