Differences between spoken and written English

As with most languages, written language tends to use a more formal register than spoken language. The acquisition of literacy takes significant effort in English.
spelling - Because of the many changes in pronunciation which have occurred since a written standard developed, the retention of many historical idiosyncrasies in spelling, and the large influx of foreign words (mainly from Danish, Norman French, Classical Latin and Greek) with different and overlapping spelling patterns, English spelling is difficult even for native speakers to master. This difficulty is shown in such activities as spelling bees that generally require the memorization of words. English speakers may also rely on computer tools such as spell checkers more than speakers of other languages, as the users of these utilities may have forgotten, or never learned, the correct spelling of a word. The generalizations that exist are quite complex and there are many exceptions leading to a considerable amount of rote learning. The spelling system causes problems in both directions - a learner may know a word by sound but not be able to write it correctly (or indeed find it in a dictionary), or they may see a word written but not know how to pronounce it or mislearn the pronunciation. However, despite the variety of spelling patterns in English, there are dozens of rules that are 75% or more reliable.