Since around the 9th century, English has been written in the Latin alphabet, which replaced Anglo-Saxon runes. The spelling system, or orthography, is multilayered, with elements of French, Latin and Greek spelling on top of the native Germanic system; it has grown to vary significantly from the phonology of the language. The spelling of words often diverges considerably from how they are spoken.

Though letters and sounds may not correspond in isolation, spelling rules that take into account syllable structure, phonetics, and accents are 75% or more reliable. Some phonics spelling advocates claim that English is more than 80% phonetic. However, English has fewer consistent relationships between sounds and letters than many other languages; for example, the letter sequence ough can be pronounced in 10 different ways. The consequence of this complex orthographic history is that reading can be challenging.

It takes longer for students to become completely fluent readers of English than of many other languages, including French, Greek, and Spanish. "English-speaking children take up to two years more to learn reading than do children in 12 other European countries."(Professor Philip H K Seymour, University of Dundee, 2001) "[dyslexia] is twice as prevalent among dyslexics in the United States (and France) as it is among Italian dyslexics. Again, this is seen to be because of Italian's 'transparent' orthography." (Eraldo Paulesu and 11 others. Science, 2001)