Spelling is always a concern for those who read and write in English. English has been shaped by many different languages, starting with Latin and Greek. Words are composed of sounds, and transcribing those sounds into written language has proved very complicated for English speakers. Some words are spelled with pronunciations that were prevalent at the times these words were invented, pronunciations that are different from today. Other words keep the spelling of the original language, even though English speakers pronounce those words differently. Homophones are words that sound the same but mean different things and are spelled differently. Usually, the etymology of two homophones proves that even though they are pronounced in the same way now, their origins are very different.
All the sounds used in speaking English words may be represented multiple ways. For instance, the letter c may make the same sound as the letter k, as well as the same sound as the letter s. In addition, certain words are spelled differently in British English and American English. Examples of this are the words labour and labor, and the words metre and meter.