Homophones
English is a vibrant, changing, dynamic language. It allows people to express their thoughts in diverse ways, as there are many synonyms and antonyms to choose from. The hardest part for the English speaker - or those learning English as a second language - is learning about homonyms. These are words that sound alike but are spelled different ways, with different meanings.
One example is "One". This word, spelled "one" means the numeral 1, an amount. If spelled "won," it means to be victorious. No wonder spelling is a difficult skill to master! Other homonyms encountered by the beginning English speaker are "to, two, too," "four, for, fore," "there, their, they're" and "son, sun" to name just a few. This is one reason that "Spell check" programs on word processing computers cannot be completely accurate, because the way a word is spelled depends on the context of the sentence. Proofreaders will always be in demand.